diff --git a/hapi-fhir-validation/src/main/java/org/hl7/fhir/common/hapi/validation/validator/FhirInstanceValidator.java b/hapi-fhir-validation/src/main/java/org/hl7/fhir/common/hapi/validation/validator/FhirInstanceValidator.java
index 09dd738a9b74..33e8844f951d 100644
--- a/hapi-fhir-validation/src/main/java/org/hl7/fhir/common/hapi/validation/validator/FhirInstanceValidator.java
+++ b/hapi-fhir-validation/src/main/java/org/hl7/fhir/common/hapi/validation/validator/FhirInstanceValidator.java
@@ -35,7 +35,7 @@ public class FhirInstanceValidator extends BaseValidatorBridge implements IInsta
 	private boolean noBindingMsgSuppressed = false;
 	private volatile VersionSpecificWorkerContextWrapper myWrappedWorkerContext;
 	private boolean errorForUnknownProfiles = true;
-	private boolean myUnknownSystemsCauseErrors = true;
+
 	private boolean assumeValidRestReferences;
 	private List<String> myExtensionDomains = Collections.emptyList();
 	private IValidatorResourceFetcher validatorResourceFetcher;
@@ -133,14 +133,6 @@ public void setBestPracticeWarningLevel(BestPracticeWarningLevel theBestPractice
 		myBestPracticeWarningLevel = theBestPracticeWarningLevel;
 	}
 
-	public void setUnknownSystemsCauseErrors(boolean theUnknownSystemsCauseErrors) {
-		myUnknownSystemsCauseErrors = theUnknownSystemsCauseErrors;
-	}
-
-	public boolean isUnknownSystemsCauseErrors() {
-		return myUnknownSystemsCauseErrors;
-	}
-
 	/**
 	 * Returns the {@link IValidationSupport validation support} in use by this validator. Default is an instance of
 	 * DefaultProfileValidationSupport if the no-arguments constructor for this object was used.
@@ -238,7 +230,6 @@ protected List<ValidationMessage> validate(IValidationContext<?> theValidationCt
 				.setAnyExtensionsAllowed(isAnyExtensionsAllowed())
 				.setBestPracticeWarningLevel(getBestPracticeWarningLevel())
 				.setErrorForUnknownProfiles(isErrorForUnknownProfiles())
-				.setUnknownSystemsCauseErrors(isUnknownSystemsCauseErrors())
 				.setExtensionDomains(getExtensionDomains())
 				.setValidationPolicyAdvisor(validatorPolicyAdvisor)
 				.setNoTerminologyChecks(isNoTerminologyChecks())
diff --git a/hapi-fhir-validation/src/main/java/org/hl7/fhir/common/hapi/validation/validator/ValidatorWrapper.java b/hapi-fhir-validation/src/main/java/org/hl7/fhir/common/hapi/validation/validator/ValidatorWrapper.java
index 2528e5577add..ac383cc3ca7e 100644
--- a/hapi-fhir-validation/src/main/java/org/hl7/fhir/common/hapi/validation/validator/ValidatorWrapper.java
+++ b/hapi-fhir-validation/src/main/java/org/hl7/fhir/common/hapi/validation/validator/ValidatorWrapper.java
@@ -47,7 +47,7 @@ class ValidatorWrapper {
 	private boolean myAssumeValidRestReferences;
 	private boolean myNoExtensibleWarnings;
 	private boolean myNoBindingMsgSuppressed;
-	private boolean myUnknownSystemsCauseErrors;
+
 	private Collection<? extends String> myExtensionDomains;
 	private IValidatorResourceFetcher myValidatorResourceFetcher;
 	private IValidationPolicyAdvisor myValidationPolicyAdvisor;
@@ -83,11 +83,6 @@ public ValidatorWrapper setErrorForUnknownProfiles(boolean theErrorForUnknownPro
 		return this;
 	}
 
-	public ValidatorWrapper setUnknownSystemsCauseErrors(boolean theUnknownSystemsCauseErrors) {
-		myUnknownSystemsCauseErrors = theUnknownSystemsCauseErrors;
-		return this;
-	}
-
 	public ValidatorWrapper setNoTerminologyChecks(boolean theNoTerminologyChecks) {
 		myNoTerminologyChecks = theNoTerminologyChecks;
 		return this;
@@ -135,7 +130,8 @@ public List<ValidationMessage> validate(
 		v.setResourceIdRule(IdStatus.OPTIONAL);
 		v.setNoTerminologyChecks(myNoTerminologyChecks);
 		v.setErrorForUnknownProfiles(myErrorForUnknownProfiles);
-		v.setUnknownCodeSystemsCauseErrors(myUnknownSystemsCauseErrors);
+		/* setUnknownCodeSystemsCauseErrors interacts with UnknownCodeSystemWarningValidationSupport. Until this interaction is resolved, the value here should remain fixed. */
+		v.setUnknownCodeSystemsCauseErrors(true);
 		v.getExtensionDomains().addAll(myExtensionDomains);
 		v.setFetcher(myValidatorResourceFetcher);
 		v.setPolicyAdvisor(myValidationPolicyAdvisor);