diff --git a/src/vs/workbench/api/electron-browser/mainThreadFileSystem.ts b/src/vs/workbench/api/electron-browser/mainThreadFileSystem.ts
index 12a40daabfa..a874c9121fe 100644
--- a/src/vs/workbench/api/electron-browser/mainThreadFileSystem.ts
+++ b/src/vs/workbench/api/electron-browser/mainThreadFileSystem.ts
@@ -14,6 +14,7 @@ import { extHostNamedCustomer } from 'vs/workbench/api/electron-browser/extHostC
 import { IProgress } from 'vs/platform/progress/common/progress';
 import { ISearchResultProvider, ISearchQuery, ISearchComplete, ISearchProgressItem, QueryType, IFileMatch, ISearchService } from 'vs/platform/search/common/search';
 import { IWorkspaceEditingService } from 'vs/workbench/services/workspace/common/workspaceEditing';
+import { onUnexpectedError } from 'vs/base/common/errors';
 
 @extHostNamedCustomer(MainContext.MainThreadFileSystem)
 export class MainThreadFileSystem implements MainThreadFileSystemShape {
@@ -45,7 +46,7 @@ export class MainThreadFileSystem implements MainThreadFileSystemShape {
 	}
 
 	$onDidAddFileSystemRoot(uri: URI): void {
-		this._workspaceEditingService.addFolders([{ uri }], true);
+		this._workspaceEditingService.addFolders([{ uri }], true).done(null, onUnexpectedError);
 	}
 
 	$onFileSystemChange(handle: number, changes: IFileChange[]): void {
diff --git a/src/vs/workbench/api/electron-browser/mainThreadWorkspace.ts b/src/vs/workbench/api/electron-browser/mainThreadWorkspace.ts
index 45836c967d0..09d921bc5b0 100644
--- a/src/vs/workbench/api/electron-browser/mainThreadWorkspace.ts
+++ b/src/vs/workbench/api/electron-browser/mainThreadWorkspace.ts
@@ -63,7 +63,7 @@ export class MainThreadWorkspace implements MainThreadWorkspaceShape {
 				return TPromise.as(false);
 			}
 
-			return this._workspaceEditingService.addFolders([{ uri, name }]).then(() => true);
+			return this._workspaceEditingService.addFolders([{ uri, name }], true).then(() => true);
 		});
 	}
 
@@ -73,7 +73,7 @@ export class MainThreadWorkspace implements MainThreadWorkspaceShape {
 				return TPromise.as(false);
 			}
 
-			return this._workspaceEditingService.removeFolders([uri]).then(() => true);
+			return this._workspaceEditingService.removeFolders([uri], true).then(() => true);
 		});
 	}