diff --git a/src/vs/workbench/api/electron-browser/mainThreadExtensionService.ts b/src/vs/workbench/api/electron-browser/mainThreadExtensionService.ts
index 7ecf4e2bd5f09478b9341cad17a1e258f34cfa6d..39ebe4816f43ebf75211e5b51e06383b882e832d 100644
--- a/src/vs/workbench/api/electron-browser/mainThreadExtensionService.ts
+++ b/src/vs/workbench/api/electron-browser/mainThreadExtensionService.ts
@@ -69,7 +69,7 @@ export class MainThreadExtensionService implements MainThreadExtensionServiceSha
 		if (typeof activationError === 'string') {
 			this._extensionService._logOrShowMessage(Severity.Error, activationError);
 		} else {
-			this._handleMissingDependency(extensionId, activationError.dependencies[0]);
+			this._handleMissingDependency(extensionId, activationError.dependency);
 		}
 	}
 
diff --git a/src/vs/workbench/api/node/extHostExtensionActivator.ts b/src/vs/workbench/api/node/extHostExtensionActivator.ts
index 15cac8c86b91cce95408837b7702b9d59c5041b5..801af83528973289c8dc065c3c266e13e66bbdc2 100644
--- a/src/vs/workbench/api/node/extHostExtensionActivator.ts
+++ b/src/vs/workbench/api/node/extHostExtensionActivator.ts
@@ -7,7 +7,7 @@ import * as nls from 'vs/nls';
 import { IDisposable } from 'vs/base/common/lifecycle';
 import { ExtensionDescriptionRegistry } from 'vs/workbench/services/extensions/node/extensionDescriptionRegistry';
 import { ExtensionIdentifier } from 'vs/platform/extensions/common/extensions';
-import { ExtensionActivationError, MissingDependenciesError } from 'vs/workbench/services/extensions/common/extensions';
+import { ExtensionActivationError, MissingDependencyError } from 'vs/workbench/services/extensions/common/extensions';
 
 const NO_OP_VOID_PROMISE = Promise.resolve<void>(undefined);
 
@@ -305,7 +305,7 @@ export class ExtensionsActivator {
 			}
 
 			// Error condition 1: unknown dependency
-			this._host.onExtensionActivationError(currentExtension.identifier, new MissingDependenciesError([depId]));
+			this._host.onExtensionActivationError(currentExtension.identifier, new MissingDependencyError(depId));
 			const error = new Error(`Unknown dependency '${depId}'`);
 			this._activatedExtensions.set(ExtensionIdentifier.toKey(currentExtension.identifier), new FailedExtension(error));
 			return;
diff --git a/src/vs/workbench/services/extensions/common/extensions.ts b/src/vs/workbench/services/extensions/common/extensions.ts
index 7c864520b92ee7ceede895e2998f065028df63e4..0f5a9baf23f78b59a557d053e3e98327a3d96f22 100644
--- a/src/vs/workbench/services/extensions/common/extensions.ts
+++ b/src/vs/workbench/services/extensions/common/extensions.ts
@@ -46,9 +46,9 @@ export interface IExtensionsStatus {
 	runtimeErrors: Error[];
 }
 
-export type ExtensionActivationError = string | MissingDependenciesError;
-export class MissingDependenciesError {
-	constructor(readonly dependencies: string[]) { }
+export type ExtensionActivationError = string | MissingDependencyError;
+export class MissingDependencyError {
+	constructor(readonly dependency: string) { }
 }
 
 /**