diff --git a/packages/horizon/contracts/data-service/interfaces/IDataService.sol b/packages/horizon/contracts/data-service/interfaces/IDataService.sol
index b7e1028f0..3eec64c04 100644
--- a/packages/horizon/contracts/data-service/interfaces/IDataService.sol
+++ b/packages/horizon/contracts/data-service/interfaces/IDataService.sol
@@ -60,11 +60,6 @@ interface IDataService {
      */
     event ServiceProviderSlashed(address indexed serviceProvider, uint256 tokens);
 
-    /**
-     * @notice Thrown to signal that a feature is not implemented by a data service.
-     */
-    error DataServiceFeatureNotImplemented();
-
     /**
      * @notice Registers a service provider with the data service. The service provider can now
      * start providing the service.
diff --git a/packages/subgraph-service/contracts/libraries/LegacyAllocation.sol b/packages/subgraph-service/contracts/libraries/LegacyAllocation.sol
index 83bef8037..c60783785 100644
--- a/packages/subgraph-service/contracts/libraries/LegacyAllocation.sol
+++ b/packages/subgraph-service/contracts/libraries/LegacyAllocation.sol
@@ -39,11 +39,12 @@ library LegacyAllocation {
     /**
      * @notice Migrate a legacy allocation
      * @dev Requirements:
-     * - The allocation must not exist
+     * - The allocation must not have been previously migrated
      * @param self The legacy allocation list mapping
      * @param indexer The indexer that owns the allocation
      * @param allocationId The allocation id
      * @param subgraphDeploymentId The subgraph deployment id the allocation is for
+     * @custom:error LegacyAllocationAlreadyMigrated if the allocation has already been migrated
      */
     function migrate(
         mapping(address => State) storage self,
@@ -51,7 +52,7 @@ library LegacyAllocation {
         address allocationId,
         bytes32 subgraphDeploymentId
     ) internal {
-        require(!self[allocationId].exists(), LegacyAllocationExists(allocationId));
+        require(!self[allocationId].exists(), LegacyAllocationAlreadyMigrated(allocationId));
 
         State memory allocation = State({ indexer: indexer, subgraphDeploymentId: subgraphDeploymentId });
         self[allocationId] = allocation;
diff --git a/packages/subgraph-service/contracts/utilities/AllocationManager.sol b/packages/subgraph-service/contracts/utilities/AllocationManager.sol
index 4ab5fd418..97c3adf99 100644
--- a/packages/subgraph-service/contracts/utilities/AllocationManager.sol
+++ b/packages/subgraph-service/contracts/utilities/AllocationManager.sol
@@ -139,13 +139,7 @@ abstract contract AllocationManager is EIP712Upgradeable, GraphDirectory, Alloca
     error AllocationManagerInvalidZeroAllocationId();
 
     /**
-     * @notice Thrown when attempting to create an allocation with zero tokens
-     * @param allocationId The id of the allocation
-     */
-    error AllocationManagerZeroTokensAllocation(address allocationId);
-
-    /**
-     * @notice Thrown when attempting to collect indexing rewards on a closed allocation
+     * @notice Thrown when attempting to collect indexing rewards on a closed allocationl
      * @param allocationId The id of the allocation
      */
     error AllocationManagerAllocationClosed(address allocationId);
@@ -178,7 +172,7 @@ abstract contract AllocationManager is EIP712Upgradeable, GraphDirectory, Alloca
     /**
      * @notice Imports a legacy allocation id into the subgraph service
      * This is a governor only action that is required to prevent indexers from re-using allocation ids from the
-     * legacy staking contract.
+     * legacy staking contract. It will revert with LegacyAllocationAlreadyMigrated if the allocation has already been migrated.
      * @param _indexer The address of the indexer
      * @param _allocationId The id of the allocation
      * @param _subgraphDeploymentId The id of the subgraph deployment