diff --git a/src/sql/platform/capabilities/common/capabilitiesService.ts b/src/sql/platform/capabilities/common/capabilitiesService.ts
index 50690bd428..ab5df93a74 100644
--- a/src/sql/platform/capabilities/common/capabilitiesService.ts
+++ b/src/sql/platform/capabilities/common/capabilitiesService.ts
@@ -132,11 +132,16 @@ export class CapabilitiesService extends Disposable implements ICapabilitiesServ
 		});
 
 		this._register(extentionManagementService.onDidUninstallExtension(({ identifier }) => {
+			const connectionProvider = 'connectionProvider';
 			let extensionid = getIdFromLocalExtensionId(identifier.id);
 			extensionService.getExtensions().then(i => {
 				let extension = i.find(c => c.id === extensionid);
-				let id = extension.contributes['connectionProvider'].providerId;
-				delete this.capabilities.connectionProviderCache[id];
+				if (extension && extension.contributes
+					&& extension.contributes[connectionProvider]
+					&& extension.contributes[connectionProvider].providerId) {
+					let id = extension.contributes[connectionProvider].providerId;
+					delete this.capabilities.connectionProviderCache[id];
+				}
 			});
 		}));
 	}
diff --git a/src/sql/workbench/services/notebook/common/notebookServiceImpl.ts b/src/sql/workbench/services/notebook/common/notebookServiceImpl.ts
index ccb67270bc..ac3803c190 100644
--- a/src/sql/workbench/services/notebook/common/notebookServiceImpl.ts
+++ b/src/sql/workbench/services/notebook/common/notebookServiceImpl.ts
@@ -158,7 +158,7 @@ export class NotebookService extends Disposable implements INotebookService {
 	}
 
 	private hookNotebookThemesAndConfigListener(): void {
-		if(this._configurationService) {
+		if (this._configurationService) {
 			this.updateNotebookThemes();
 			this._register(this._configurationService.onDidChangeConfiguration(e => {
 				if (e.affectsConfiguration(OVERRIDE_EDITOR_THEMING_SETTING)) {
@@ -458,11 +458,14 @@ export class NotebookService extends Disposable implements INotebookService {
 	}
 
 	private removeContributedProvidersFromCache(identifier: IExtensionIdentifier, extensionService: IExtensionService) {
+		const notebookProvider = 'notebookProvider';
 		let extensionid = getIdFromLocalExtensionId(identifier.id);
 		extensionService.getExtensions().then(i => {
 			let extension = i.find(c => c.id === extensionid);
-			if (extension && extension.contributes['notebookProvider']) {
-				let id = extension.contributes['notebookProvider'].providerId;
+			if (extension && extension.contributes
+				&& extension.contributes[notebookProvider]
+				&& extension.contributes[notebookProvider].providerId) {
+				let id = extension.contributes[notebookProvider].providerId;
 				delete this.providersMemento.notebookProviderCache[id];
 			}
 		});