diff --git a/internal/provider/resource_account_resource.go b/internal/provider/resource_account_resource.go
index c399e66..8652e46 100644
--- a/internal/provider/resource_account_resource.go
+++ b/internal/provider/resource_account_resource.go
@@ -170,6 +170,12 @@ func (r *ResourceAccountResource) Read(ctx context.Context, req resource.ReadReq
 		return
 	}
 
+	if httpResp.StatusCode() == 404 {
+		resp.Diagnostics.AddWarning("Resource account not found", fmt.Sprintf("The resource account (%s) was deleted outside Terraform", data.ID.ValueString()))
+		resp.State.RemoveResource(ctx)
+		return
+	}
+
 	if httpResp.StatusCode() != 200 {
 		resp.Diagnostics.AddError(HUM_API_ERR, fmt.Sprintf("Unable to read resource account, unexpected status code: %d, body: %s", httpResp.StatusCode(), httpResp.Body))
 		return
diff --git a/internal/provider/resource_account_resource_test.go b/internal/provider/resource_account_resource_test.go
index 4ec3483..93f41cf 100644
--- a/internal/provider/resource_account_resource_test.go
+++ b/internal/provider/resource_account_resource_test.go
@@ -1,15 +1,21 @@
 package provider
 
 import (
+	"context"
 	"fmt"
+	"os"
 	"testing"
 	"time"
 
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/resource"
+	"github.com/hashicorp/terraform-plugin-sdk/v2/terraform"
+	"github.com/humanitec/humanitec-go-autogen"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestAccResourceAccountResource(t *testing.T) {
 	id := fmt.Sprintf("gcp-test-%d", time.Now().UnixNano())
+	email := fmt.Sprintf("gpc-myemail-%d@email.com", time.Now().UnixNano())
 
 	resource.Test(t, resource.TestCase{
 		PreCheck:                 func() { testAccPreCheck(t) },
@@ -17,7 +23,7 @@ func TestAccResourceAccountResource(t *testing.T) {
 		Steps: []resource.TestStep{
 			// Create and Read testing
 			{
-				Config: testAccResourceAccountResource(id, "gcp-test-1"),
+				Config: testAccResourceAccountResource(id, "gcp-test-1", email),
 				Check: resource.ComposeAggregateTestCheckFunc(
 					resource.TestCheckResourceAttr("humanitec_resource_account.gcp_test", "id", id),
 					resource.TestCheckResourceAttr("humanitec_resource_account.gcp_test", "name", "gcp-test-1"),
@@ -32,7 +38,7 @@ func TestAccResourceAccountResource(t *testing.T) {
 			},
 			// Update and Read testing
 			{
-				Config: testAccResourceAccountResource(id, "gcp-test-2"),
+				Config: testAccResourceAccountResource(id, "gcp-test-2", email),
 				Check: resource.ComposeAggregateTestCheckFunc(
 					resource.TestCheckResourceAttr("humanitec_resource_account.gcp_test", "name", "gcp-test-2"),
 				),
@@ -42,13 +48,65 @@ func TestAccResourceAccountResource(t *testing.T) {
 	})
 }
 
-func testAccResourceAccountResource(id, name string) string {
+func TestAccResourceAccountResource_DeletedManually(t *testing.T) {
+	assert := assert.New(t)
+	ctx := context.Background()
+	id := fmt.Sprintf("gcp-test-%d", time.Now().UnixNano())
+	email := fmt.Sprintf("gpc-myemail-%d@email.com", time.Now().UnixNano())
+
+	orgID := os.Getenv("HUMANITEC_ORG")
+	token := os.Getenv("HUMANITEC_TOKEN")
+	apiHost := os.Getenv("HUMANITEC_HOST")
+	if apiHost == "" {
+		apiHost = humanitec.DefaultAPIHost
+	}
+
+	var client *humanitec.Client
+	var err error
+
+	resource.Test(t, resource.TestCase{
+		PreCheck: func() {
+			testAccPreCheck(t)
+
+			client, err = NewHumanitecClient(apiHost, token, "test", nil)
+			assert.NoError(err)
+		},
+		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccResourceAccountResource(id, "gcp-test-2", email),
+				Check: resource.ComposeAggregateTestCheckFunc(
+					resource.TestCheckResourceAttr("humanitec_resource_account.gcp_test", "id", id),
+					func(_ *terraform.State) error {
+						// Manually delete the resource account via the API
+						resp, err := client.DeleteResourceAccountWithResponse(ctx, orgID, id)
+						if err != nil {
+							return err
+						}
+
+						if resp.StatusCode() != 204 {
+							return fmt.Errorf("expected status code 204, got %d, body: %s", resp.StatusCode(), string(resp.Body))
+						}
+
+						return nil
+					},
+				),
+				ExpectNonEmptyPlan: true,
+			},
+		},
+	})
+}
+
+func testAccResourceAccountResource(id, name, email string) string {
 	return fmt.Sprintf(`
 resource "humanitec_resource_account" "gcp_test" {
   id          = "%s"
   name        = "%s"
   type        = "gcp"
-  credentials = "{}"
+  credentials = jsonencode({
+   client_email = "%s" 
+   private_key = "mykey"
+  })
 }
-`, id, name)
+`, id, name, email)
 }
diff --git a/internal/provider/resource_agent.go b/internal/provider/resource_agent.go
index ed5da1d..9cb1f46 100644
--- a/internal/provider/resource_agent.go
+++ b/internal/provider/resource_agent.go
@@ -217,7 +217,8 @@ func (a *Agent) Read(ctx context.Context, req resource.ReadRequest, resp *resour
 			}
 		}
 		if agent == nil {
-			resp.Diagnostics.AddError(HUM_API_ERR, fmt.Sprintf("Can't find agent %s in organization agent list", id))
+			resp.Diagnostics.AddWarning("Agent not found", fmt.Sprintf("The agent (%s) was deleted outside Terraform", data.ID.ValueString()))
+			resp.State.RemoveResource(ctx)
 			return
 		}
 	default:
diff --git a/internal/provider/resource_agent_test.go b/internal/provider/resource_agent_test.go
index 0579c8a..ed29fa0 100644
--- a/internal/provider/resource_agent_test.go
+++ b/internal/provider/resource_agent_test.go
@@ -1,16 +1,19 @@
 package provider
 
 import (
+	"context"
 	"crypto/rand"
 	"crypto/rsa"
 	"crypto/x509"
 	"encoding/pem"
 	"fmt"
+	"os"
 	"testing"
 	"time"
 
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/resource"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/terraform"
+	"github.com/humanitec/humanitec-go-autogen"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -77,7 +80,56 @@ func TestAccAgent(t *testing.T) {
 			// Delete testing automatically occurs in TestCase
 		},
 	})
+}
+
+func TestAccResourceAgent_DeletedManually(t *testing.T) {
+	assert := assert.New(t)
+	ctx := context.Background()
+	id := fmt.Sprintf("agent-test-%d", time.Now().UnixNano())
 
+	orgID := os.Getenv("HUMANITEC_ORG")
+	token := os.Getenv("HUMANITEC_TOKEN")
+	apiHost := os.Getenv("HUMANITEC_HOST")
+	if apiHost == "" {
+		apiHost = humanitec.DefaultAPIHost
+	}
+
+	var client *humanitec.Client
+	var err error
+	publicKeyOne := getPublicKey(t)
+	publicKeyTwo := getPublicKey(t)
+
+	resource.Test(t, resource.TestCase{
+		PreCheck: func() {
+			testAccPreCheck(t)
+
+			client, err = NewHumanitecClient(apiHost, token, "test", nil)
+			assert.NoError(err)
+		},
+		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccCreateAgent(id, "my agent", publicKeyOne, publicKeyTwo),
+				Check: resource.ComposeAggregateTestCheckFunc(
+					resource.TestCheckResourceAttr("humanitec_agent.agent_test", "public_keys.#", "2"),
+					func(_ *terraform.State) error {
+						// Manually delete the agent via the API
+						resp, err := client.DeleteAgentWithResponse(ctx, orgID, id)
+						if err != nil {
+							return err
+						}
+
+						if resp.StatusCode() != 204 {
+							return fmt.Errorf("expected status code 204, got %d, body: %s", resp.StatusCode(), string(resp.Body))
+						}
+
+						return nil
+					},
+				),
+				ExpectNonEmptyPlan: true,
+			},
+		},
+	})
 }
 
 func testAccCreateAgent(id, description string, publicKey, otherPublicKey string) string {
diff --git a/internal/provider/resource_application_test.go b/internal/provider/resource_application_test.go
index d9277dd..8116f8b 100644
--- a/internal/provider/resource_application_test.go
+++ b/internal/provider/resource_application_test.go
@@ -46,6 +46,10 @@ func TestAccResourceApplicationDeletedOutManually(t *testing.T) {
 
 	orgID := os.Getenv("HUMANITEC_ORG")
 	token := os.Getenv("HUMANITEC_TOKEN")
+	apiHost := os.Getenv("HUMANITEC_HOST")
+	if apiHost == "" {
+		apiHost = humanitec.DefaultAPIHost
+	}
 
 	var client *humanitec.Client
 	var err error
@@ -54,7 +58,7 @@ func TestAccResourceApplicationDeletedOutManually(t *testing.T) {
 		PreCheck: func() {
 			testAccPreCheck(t)
 
-			client, err = NewHumanitecClient(humanitec.DefaultAPIHost, token, "test", nil)
+			client, err = NewHumanitecClient(apiHost, token, "test", nil)
 			assert.NoError(err)
 		},
 		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
diff --git a/internal/provider/resource_application_user_test.go b/internal/provider/resource_application_user_test.go
index cae4561..09d5fc9 100644
--- a/internal/provider/resource_application_user_test.go
+++ b/internal/provider/resource_application_user_test.go
@@ -58,6 +58,10 @@ func TestAccResourceApplicationUserDeletedManually(t *testing.T) {
 
 	orgID := os.Getenv("HUMANITEC_ORG")
 	token := os.Getenv("HUMANITEC_TOKEN")
+	apiHost := os.Getenv("HUMANITEC_HOST")
+	if apiHost == "" {
+		apiHost = humanitec.DefaultAPIHost
+	}
 
 	var client *humanitec.Client
 	var err error
@@ -66,17 +70,17 @@ func TestAccResourceApplicationUserDeletedManually(t *testing.T) {
 		PreCheck: func() {
 			testAccPreCheck(t)
 
-			client, err = NewHumanitecClient(humanitec.DefaultAPIHost, token, "test", nil)
+			client, err = NewHumanitecClient(apiHost, token, "test", nil)
 			assert.NoError(err)
 		},
 		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
 		Steps: []resource.TestStep{
 			// Create and Read testing
 			{
-				Config: testAccResourceApplicationUser(id, testUserID, "owner"),
+				Config: testAccResourceApplicationUser(id, testUserID, "developer"),
 				Check: resource.ComposeAggregateTestCheckFunc(
 					resource.TestCheckResourceAttr("humanitec_application_user.another_user", "id", fmt.Sprintf("%s/%s", id, testUserID)),
-					resource.TestCheckResourceAttr("humanitec_application_user.another_user", "role", "owner"),
+					resource.TestCheckResourceAttr("humanitec_application_user.another_user", "role", "developer"),
 					func(_ *terraform.State) error {
 						// Manually delete the application via the API
 						resp, err := client.DeleteApplicationWithResponse(ctx, orgID, id)
diff --git a/internal/provider/resource_environment_type_user_test.go b/internal/provider/resource_environment_type_user_test.go
index 0a74097..1cf8282 100644
--- a/internal/provider/resource_environment_type_user_test.go
+++ b/internal/provider/resource_environment_type_user_test.go
@@ -59,6 +59,10 @@ func TestAccResourceEnvironmentTypeUserDeletedManually(t *testing.T) {
 
 	orgID := os.Getenv("HUMANITEC_ORG")
 	token := os.Getenv("HUMANITEC_TOKEN")
+	apiHost := os.Getenv("HUMANITEC_HOST")
+	if apiHost == "" {
+		apiHost = humanitec.DefaultAPIHost
+	}
 
 	var client *humanitec.Client
 	var err error
@@ -67,7 +71,7 @@ func TestAccResourceEnvironmentTypeUserDeletedManually(t *testing.T) {
 		PreCheck: func() {
 			testAccPreCheck(t)
 
-			client, err = NewHumanitecClient(humanitec.DefaultAPIHost, token, "test", nil)
+			client, err = NewHumanitecClient(apiHost, token, "test", nil)
 			assert.NoError(err)
 		},
 		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
@@ -79,7 +83,7 @@ func TestAccResourceEnvironmentTypeUserDeletedManually(t *testing.T) {
 					resource.TestCheckResourceAttr("humanitec_environment_type_user.another_user", "id", fmt.Sprintf("%s/%s", id, testUserID)),
 					resource.TestCheckResourceAttr("humanitec_environment_type_user.another_user", "role", "deployer"),
 					func(_ *terraform.State) error {
-						// Manually delete the application via the API
+						// Manually delete the environment type via the API
 						resp, err := client.DeleteEnvironmentTypeWithResponse(ctx, orgID, id)
 						if err != nil {
 							return err
diff --git a/internal/provider/resource_key_test.go b/internal/provider/resource_key_test.go
index 3df7091..fd91e6f 100644
--- a/internal/provider/resource_key_test.go
+++ b/internal/provider/resource_key_test.go
@@ -1,11 +1,15 @@
 package provider
 
 import (
+	"context"
 	"fmt"
+	"os"
 	"testing"
 
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/resource"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/terraform"
+	"github.com/humanitec/humanitec-go-autogen"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestAccResourceKeys(t *testing.T) {
@@ -43,6 +47,73 @@ func TestAccResourceKeys(t *testing.T) {
 	})
 }
 
+func TestAccResourceKey_DeletedManually(t *testing.T) {
+	assert := assert.New(t)
+	ctx := context.Background()
+
+	orgID := os.Getenv("HUMANITEC_ORG")
+	token := os.Getenv("HUMANITEC_TOKEN")
+	apiHost := os.Getenv("HUMANITEC_HOST")
+	if apiHost == "" {
+		apiHost = humanitec.DefaultAPIHost
+	}
+
+	var client *humanitec.Client
+	var err error
+
+	key := getPublicKey(t)
+	var id string
+
+	resource.Test(t, resource.TestCase{
+		PreCheck: func() {
+			testAccPreCheck(t)
+
+			client, err = NewHumanitecClient(apiHost, token, "test", nil)
+			assert.NoError(err)
+		},
+		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
+		Steps: []resource.TestStep{
+			// Create and Read testing
+			{
+				Config: testAccResourceKey(key),
+				Check: resource.ComposeAggregateTestCheckFunc(
+					resource.TestCheckResourceAttr("humanitec_key.key_test", "key", key),
+					resource.TestCheckResourceAttrSet("humanitec_key.key_test", "id"),
+					resource.TestCheckResourceAttrSet("humanitec_key.key_test", "fingerprint"),
+				),
+			},
+			// ImportState testing
+			{
+				ResourceName:      "humanitec_key.key_test",
+				ImportState:       true,
+				ImportStateVerify: true,
+				ImportStateIdFunc: func(s *terraform.State) (string, error) {
+					id = s.RootModule().Resources["humanitec_key.key_test"].Primary.Attributes["id"]
+					return id, nil
+				},
+				Check: resource.ComposeAggregateTestCheckFunc(
+					resource.TestCheckResourceAttr("humanitec_key.key_test", "key", key),
+					resource.TestCheckResourceAttr("humanitec_key.key_test", "id", id),
+					func(_ *terraform.State) error {
+						// Manually delete the public key via the API
+						resp, err := client.DeletePublicKeyWithResponse(ctx, orgID, id)
+						if err != nil {
+							return err
+						}
+
+						if resp.StatusCode() != 204 {
+							return fmt.Errorf("expected status code 204, got %d, body: %s", resp.StatusCode(), string(resp.Body))
+						}
+
+						return nil
+					},
+				),
+				ExpectNonEmptyPlan: true,
+			},
+		},
+	})
+}
+
 func testAccResourceKey(key string) string {
 	return fmt.Sprintf(`
 	resource "humanitec_key" "key_test" {
diff --git a/internal/provider/resource_resource_class.go b/internal/provider/resource_resource_class.go
index 2ecd4b8..58e2dc5 100644
--- a/internal/provider/resource_resource_class.go
+++ b/internal/provider/resource_resource_class.go
@@ -142,6 +142,12 @@ func (r *ResourceResourceClass) Read(ctx context.Context, req resource.ReadReque
 		return
 	}
 
+	if httpResp.StatusCode() == 404 {
+		resp.Diagnostics.AddWarning("Resource class not found", fmt.Sprintf("The resource class (%s) was deleted outside Terraform", data.ID.ValueString()))
+		resp.State.RemoveResource(ctx)
+		return
+	}
+
 	if httpResp.StatusCode() != 200 {
 		resp.Diagnostics.AddError(HUM_API_ERR, fmt.Sprintf("Unable to read resource class, unexpected status code: %d, body: %s", httpResp.StatusCode(), httpResp.Body))
 		return
diff --git a/internal/provider/resource_resource_class_test.go b/internal/provider/resource_resource_class_test.go
index 8b2f636..a80fe21 100644
--- a/internal/provider/resource_resource_class_test.go
+++ b/internal/provider/resource_resource_class_test.go
@@ -1,12 +1,16 @@
 package provider
 
 import (
+	"context"
 	"fmt"
+	"os"
 	"testing"
 	"time"
 
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/resource"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/terraform"
+	"github.com/humanitec/humanitec-go-autogen"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestAccResourceClass(t *testing.T) {
@@ -51,6 +55,56 @@ func TestAccResourceClass(t *testing.T) {
 	})
 }
 
+func TestAccResourceClass_DeletedManually(t *testing.T) {
+	assert := assert.New(t)
+	ctx := context.Background()
+	id := fmt.Sprintf("test-class-%d", time.Now().UnixNano())
+	description := "test-description"
+	resourceType := "mysql"
+
+	orgID := os.Getenv("HUMANITEC_ORG")
+	token := os.Getenv("HUMANITEC_TOKEN")
+	apiHost := os.Getenv("HUMANITEC_HOST")
+	if apiHost == "" {
+		apiHost = humanitec.DefaultAPIHost
+	}
+
+	var client *humanitec.Client
+	var err error
+
+	resource.Test(t, resource.TestCase{
+		PreCheck: func() {
+			testAccPreCheck(t)
+
+			client, err = NewHumanitecClient(apiHost, token, "test", nil)
+			assert.NoError(err)
+		},
+		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccResourceClass(id, description, resourceType),
+				Check: resource.ComposeAggregateTestCheckFunc(
+					resource.TestCheckResourceAttr("humanitec_resource_class.class_test", "id", id),
+					func(_ *terraform.State) error {
+						// Manually delete the resource class via the API
+						resp, err := client.DeleteResourceClassWithResponse(ctx, orgID, resourceType, id)
+						if err != nil {
+							return err
+						}
+
+						if resp.StatusCode() != 204 {
+							return fmt.Errorf("expected status code 204, got %d, body: %s", resp.StatusCode(), string(resp.Body))
+						}
+
+						return nil
+					},
+				),
+				ExpectNonEmptyPlan: true,
+			},
+		},
+	})
+}
+
 func testAccResourceClass(id, description, resourceType string) string {
 	return fmt.Sprintf(`
 resource "humanitec_resource_class" "class_test" {
diff --git a/internal/provider/resource_resource_driver.go b/internal/provider/resource_resource_driver.go
index b383190..69fde37 100644
--- a/internal/provider/resource_resource_driver.go
+++ b/internal/provider/resource_resource_driver.go
@@ -212,6 +212,12 @@ func (r *ResourceResourceDriver) Read(ctx context.Context, req resource.ReadRequ
 		return
 	}
 
+	if httpResp.StatusCode() == 404 {
+		resp.Diagnostics.AddWarning("Resource driver not found", fmt.Sprintf("The resource driver (%s) was deleted outside Terraform", data.ID.ValueString()))
+		resp.State.RemoveResource(ctx)
+		return
+	}
+
 	if httpResp.StatusCode() != 200 {
 		resp.Diagnostics.AddError(HUM_API_ERR, fmt.Sprintf("Unable to read resource driver, unexpected status code: %d, body: %s", httpResp.StatusCode(), httpResp.Body))
 		return
diff --git a/internal/provider/resource_resource_driver_test.go b/internal/provider/resource_resource_driver_test.go
index c26bc16..53dd1d2 100644
--- a/internal/provider/resource_resource_driver_test.go
+++ b/internal/provider/resource_resource_driver_test.go
@@ -1,11 +1,16 @@
 package provider
 
 import (
+	"context"
 	"fmt"
+	"os"
 	"testing"
 	"time"
 
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/resource"
+	"github.com/hashicorp/terraform-plugin-sdk/v2/terraform"
+	"github.com/humanitec/humanitec-go-autogen"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestAccResourceResourceDriver(t *testing.T) {
@@ -76,6 +81,54 @@ func TestAccResourceResourceDriver(t *testing.T) {
 	}
 }
 
+func TestAccResourceDriver_DeletedManually(t *testing.T) {
+	assert := assert.New(t)
+	ctx := context.Background()
+	id := fmt.Sprintf("driver-%d", time.Now().UnixNano())
+
+	orgID := os.Getenv("HUMANITEC_ORG")
+	token := os.Getenv("HUMANITEC_TOKEN")
+	apiHost := os.Getenv("HUMANITEC_HOST")
+	if apiHost == "" {
+		apiHost = humanitec.DefaultAPIHost
+	}
+
+	var client *humanitec.Client
+	var err error
+
+	resource.Test(t, resource.TestCase{
+		PreCheck: func() {
+			testAccPreCheck(t)
+
+			client, err = NewHumanitecClient(apiHost, token, "test", nil)
+			assert.NoError(err)
+		},
+		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccResourceResourceDriver(id, "http://driver.driver:8080/driver"),
+				Check: resource.ComposeAggregateTestCheckFunc(
+					resource.TestCheckResourceAttr("humanitec_resource_driver.s3", "target", "http://driver.driver:8080/driver"),
+					func(_ *terraform.State) error {
+						// Manually delete the resource driver via the API
+						resp, err := client.DeleteResourceDriverWithResponse(ctx, orgID, id)
+						if err != nil {
+							return err
+						}
+
+						if resp.StatusCode() != 204 {
+							return fmt.Errorf("expected status code 204, got %d, body: %s", resp.StatusCode(), string(resp.Body))
+						}
+
+						return nil
+					},
+				),
+				ExpectNonEmptyPlan: true,
+			},
+		},
+	})
+}
+
 func testAccResourceResourceDriver(id, target string) string {
 	return fmt.Sprintf(`
 resource "humanitec_resource_driver" "s3" {
diff --git a/internal/provider/resource_rule.go b/internal/provider/resource_rule.go
index 0c73bfc..1b23a16 100644
--- a/internal/provider/resource_rule.go
+++ b/internal/provider/resource_rule.go
@@ -209,6 +209,11 @@ func (r *ResourceRule) Read(ctx context.Context, req resource.ReadRequest, resp
 		resp.Diagnostics.AddError(HUM_CLIENT_ERR, fmt.Sprintf("Unable to read rule, got error: %s", err))
 		return
 	}
+	if httpResp.StatusCode() == 404 {
+		resp.Diagnostics.AddWarning("Rule not found", fmt.Sprintf("The rule (%s) was deleted outside Terraform", data.ID.ValueString()))
+		resp.State.RemoveResource(ctx)
+		return
+	}
 	if httpResp.StatusCode() != 200 {
 		resp.Diagnostics.AddError(HUM_API_ERR, fmt.Sprintf("Unable to read rule, unexpected status code: %d, body: %s", httpResp.StatusCode(), httpResp.Body))
 		return
diff --git a/internal/provider/resource_rule_test.go b/internal/provider/resource_rule_test.go
index 2a4244a..9c21a2b 100644
--- a/internal/provider/resource_rule_test.go
+++ b/internal/provider/resource_rule_test.go
@@ -1,12 +1,16 @@
 package provider
 
 import (
+	"context"
 	"fmt"
+	"os"
 	"testing"
 	"time"
 
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/resource"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/terraform"
+	"github.com/humanitec/humanitec-go-autogen"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestAccResourceRule(t *testing.T) {
@@ -73,6 +77,71 @@ func TestAccResourceRule(t *testing.T) {
 	}
 }
 
+func TestAccResourceRule_DeletedManually(t *testing.T) {
+	assert := assert.New(t)
+	ctx := context.Background()
+	appId := fmt.Sprintf("tf-rule-%d", time.Now().UnixNano())
+
+	orgID := os.Getenv("HUMANITEC_ORG")
+	token := os.Getenv("HUMANITEC_TOKEN")
+	apiHost := os.Getenv("HUMANITEC_HOST")
+	if apiHost == "" {
+		apiHost = humanitec.DefaultAPIHost
+	}
+
+	var client *humanitec.Client
+	var err error
+	var id string
+
+	resource.Test(t, resource.TestCase{
+		PreCheck: func() {
+			testAccPreCheck(t)
+
+			client, err = NewHumanitecClient(apiHost, token, "test", nil)
+			assert.NoError(err)
+		},
+		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccResourceRule(appId, "my-artefact"),
+				Check: resource.ComposeAggregateTestCheckFunc(
+					resource.TestCheckResourceAttr("humanitec_rule.rule1", "artefacts_filter.0", "my-artefact"),
+				),
+			},
+			{
+				ResourceName:      "humanitec_rule.rule1",
+				ImportState:       true,
+				ImportStateVerify: true,
+				ImportStateIdFunc: func(s *terraform.State) (string, error) {
+					rule, err := testResource("humanitec_rule.rule1", s)
+					if err != nil {
+						return "", err
+					}
+					id = fmt.Sprintf("%s/dev/%s", appId, rule.Primary.ID)
+					return id, nil
+				},
+				Check: resource.ComposeAggregateTestCheckFunc(
+					resource.TestCheckResourceAttr("humanitec_rule.rule1", "id", id),
+					func(_ *terraform.State) error {
+						// Manually delete the rule via the API
+						resp, err := client.DeleteAutomationRuleWithResponse(ctx, orgID, appId, "dev", id)
+						if err != nil {
+							return err
+						}
+
+						if resp.StatusCode() != 204 {
+							return fmt.Errorf("expected status code 204, got %d, body: %s", resp.StatusCode(), string(resp.Body))
+						}
+
+						return nil
+					},
+				),
+				ExpectNonEmptyPlan: true,
+			},
+		},
+	})
+}
+
 func testAccResourceRule(appID, artefact string) string {
 	return fmt.Sprintf(`
 	resource "humanitec_application" "rule_test" {
diff --git a/internal/provider/resource_secret_store.go b/internal/provider/resource_secret_store.go
index 0ea86d3..d97e6fc 100644
--- a/internal/provider/resource_secret_store.go
+++ b/internal/provider/resource_secret_store.go
@@ -377,6 +377,13 @@ func (s *SecretStore) Read(ctx context.Context, req resource.ReadRequest, resp *
 		resp.Diagnostics.AddError(HUM_CLIENT_ERR, fmt.Sprintf("Unable to read secret store, got error: %s", err))
 		return
 	}
+
+	if httpResp.StatusCode() == 404 {
+		resp.Diagnostics.AddWarning("Secret store not found", fmt.Sprintf("The secret store (%s) was deleted outside Terraform", data.ID.ValueString()))
+		resp.State.RemoveResource(ctx)
+		return
+	}
+
 	if httpResp.StatusCode() != 200 {
 		resp.Diagnostics.AddError(HUM_API_ERR, fmt.Sprintf("Unable to read secret store, unexpected status code: %d, body: %s", httpResp.StatusCode(), httpResp.Body))
 		return
diff --git a/internal/provider/resource_secret_store_test.go b/internal/provider/resource_secret_store_test.go
index e1c2627..89bc2dd 100644
--- a/internal/provider/resource_secret_store_test.go
+++ b/internal/provider/resource_secret_store_test.go
@@ -1,12 +1,16 @@
 package provider
 
 import (
+	"context"
 	"fmt"
+	"os"
 	"testing"
 	"time"
 
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/resource"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/terraform"
+	"github.com/humanitec/humanitec-go-autogen"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestAccResourceSecretStore_AzureKV(t *testing.T) {
@@ -209,6 +213,54 @@ func TestAccResourceSecretStore_Vault_RemoveAuth(t *testing.T) {
 	})
 }
 
+func TestAccResourceSecretStore_DeletedManually(t *testing.T) {
+	assert := assert.New(t)
+	ctx := context.Background()
+	id := fmt.Sprintf("secret-store-%d", time.Now().UnixNano())
+
+	orgID := os.Getenv("HUMANITEC_ORG")
+	token := os.Getenv("HUMANITEC_TOKEN")
+	apiHost := os.Getenv("HUMANITEC_HOST")
+	if apiHost == "" {
+		apiHost = humanitec.DefaultAPIHost
+	}
+
+	var client *humanitec.Client
+	var err error
+
+	resource.Test(t, resource.TestCase{
+		PreCheck: func() {
+			testAccPreCheck(t)
+
+			client, err = NewHumanitecClient(apiHost, token, "test", nil)
+			assert.NoError(err)
+		},
+		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccSecretStoreVaultNoAuth(id, "dumburl", false),
+				Check: resource.ComposeAggregateTestCheckFunc(
+					resource.TestCheckResourceAttr("humanitec_secretstore.secret_store_vault_test", "vault.url", "dumburl"),
+					func(_ *terraform.State) error {
+						// Manually delete the secret store via the API
+						resp, err := client.DeleteOrgsOrgIdSecretstoresStoreIdWithResponse(ctx, orgID, id)
+						if err != nil {
+							return err
+						}
+
+						if resp.StatusCode() != 204 {
+							return fmt.Errorf("expected status code 204, got %d, body: %s", resp.StatusCode(), string(resp.Body))
+						}
+
+						return nil
+					},
+				),
+				ExpectNonEmptyPlan: true,
+			},
+		},
+	})
+}
+
 func testAccSecretStoreAzureKV(storeID, tenantID, url, clientID, clientSecret string) string {
 	return fmt.Sprintf(`
 	resource "humanitec_secretstore" "secret_store_azurekv_test" {
diff --git a/internal/provider/resource_value_test.go b/internal/provider/resource_value_test.go
index 5801d86..cae3131 100644
--- a/internal/provider/resource_value_test.go
+++ b/internal/provider/resource_value_test.go
@@ -197,6 +197,10 @@ func TestAccResourceValueDeletedOutManually(t *testing.T) {
 
 	orgID := os.Getenv("HUMANITEC_ORG")
 	token := os.Getenv("HUMANITEC_TOKEN")
+	apiHost := os.Getenv("HUMANITEC_HOST")
+	if apiHost == "" {
+		apiHost = humanitec.DefaultAPIHost
+	}
 
 	var client *humanitec.Client
 	var err error
@@ -205,7 +209,7 @@ func TestAccResourceValueDeletedOutManually(t *testing.T) {
 		PreCheck: func() {
 			testAccPreCheck(t)
 
-			client, err = NewHumanitecClient(humanitec.DefaultAPIHost, token, "test", nil)
+			client, err = NewHumanitecClient(apiHost, token, "test", nil)
 			assert.NoError(err)
 		},
 		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,