diff --git a/src/vs/vscode.proposed.d.ts b/src/vs/vscode.proposed.d.ts
index bb0f578552b..ac12244ade0 100644
--- a/src/vs/vscode.proposed.d.ts
+++ b/src/vs/vscode.proposed.d.ts
@@ -995,6 +995,16 @@ declare module 'vscode' {
 
 	}
 
+	export class UserDataError extends Error {
+
+		static VersionExists(): FileSystemError;
+
+		/**
+		 * Creates a new userData error.
+		 */
+		constructor();
+	}
+
 	export interface UserDataProvider {
 
 		read(key: string): Promise<{ version: number, content: string } | null>;
diff --git a/src/vs/workbench/api/common/extHost.api.impl.ts b/src/vs/workbench/api/common/extHost.api.impl.ts
index e21f6563b02..c7c285a15e3 100644
--- a/src/vs/workbench/api/common/extHost.api.impl.ts
+++ b/src/vs/workbench/api/common/extHost.api.impl.ts
@@ -897,7 +897,8 @@ export function createApiFactoryAndRegisterActors(accessor: ServicesAccessor): I
 			// proposed
 			CallHierarchyDirection: extHostTypes.CallHierarchyDirection,
 			CallHierarchyItem: extHostTypes.CallHierarchyItem,
-			Decoration: extHostTypes.Decoration
+			Decoration: extHostTypes.Decoration,
+			UserDataError: extHostTypes.UserDataError
 		};
 	};
 }
diff --git a/src/vs/workbench/api/common/extHostTypes.ts b/src/vs/workbench/api/common/extHostTypes.ts
index 623297aa26d..6d19f8d7669 100644
--- a/src/vs/workbench/api/common/extHostTypes.ts
+++ b/src/vs/workbench/api/common/extHostTypes.ts
@@ -14,6 +14,7 @@ import { generateUuid } from 'vs/base/common/uuid';
 import * as vscode from 'vscode';
 import { FileSystemProviderErrorCode, markAsFileSystemProviderError } from 'vs/platform/files/common/files';
 import { RemoteAuthorityResolverErrorCode } from 'vs/platform/remote/common/remoteAuthorityResolver';
+import { RemoteUserDataErrorCode, markAsUserDataError } from 'vs/workbench/services/userData/common/userData';
 
 function es5ClassCompat(target: Function): any {
 	///@ts-ignore
@@ -2367,3 +2368,25 @@ export class Decoration {
 	priority?: number;
 	bubble?: boolean;
 }
+
+@es5ClassCompat
+export class UserDataError extends Error {
+
+	static VersionExists(message?: string): UserDataError {
+		return new UserDataError(message, RemoteUserDataErrorCode.VersionExists);
+	}
+
+	constructor(message?: string, code: RemoteUserDataErrorCode = RemoteUserDataErrorCode.Unknown) {
+		super(message);
+
+		// mark the error as user data provider error so that
+		// we can extract the error code on the receiving side
+		markAsUserDataError(this, code);
+
+		// workaround when extending builtin objects and when compiling to ES5, see:
+		// https://github.com/Microsoft/TypeScript-wiki/blob/master/Breaking-Changes.md#extending-built-ins-like-error-array-and-map-may-no-longer-work
+		if (typeof (<any>Object).setPrototypeOf === 'function') {
+			(<any>Object).setPrototypeOf(this, UserDataError.prototype);
+		}
+	}
+}
diff --git a/src/vs/workbench/services/userData/common/remoteUserDataService.ts b/src/vs/workbench/services/userData/common/remoteUserDataService.ts
index 2e71e26f455..c244ae82529 100644
--- a/src/vs/workbench/services/userData/common/remoteUserDataService.ts
+++ b/src/vs/workbench/services/userData/common/remoteUserDataService.ts
@@ -6,7 +6,7 @@
 import { Disposable, } from 'vs/base/common/lifecycle';
 import { registerSingleton } from 'vs/platform/instantiation/common/extensions';
 import { Emitter, Event } from 'vs/base/common/event';
-import { IRemoteUserDataService, IRemoteUserDataProvider, IUserData } from 'vs/workbench/services/userData/common/userData';
+import { IRemoteUserDataService, IRemoteUserDataProvider, IUserData, RemoteUserDataError, toUserDataErrorCode } from 'vs/workbench/services/userData/common/userData';
 import { ILogService } from 'vs/platform/log/common/log';
 
 export class RemoteUserDataService extends Disposable implements IRemoteUserDataService {
@@ -53,14 +53,16 @@ export class RemoteUserDataService extends Disposable implements IRemoteUserData
 		if (!this.remoteUserDataProvider) {
 			throw new Error('No remote user data provider exists.');
 		}
-		return this.remoteUserDataProvider.read(key);
+		return this.remoteUserDataProvider.read(key)
+			.then(null, error => Promise.reject(new RemoteUserDataError(error.message, toUserDataErrorCode(error))));
 	}
 
 	write(key: string, version: number, content: string): Promise<void> {
 		if (!this.remoteUserDataProvider) {
 			throw new Error('No remote user data provider exists.');
 		}
-		return this.remoteUserDataProvider.write(key, version, content);
+		return this.remoteUserDataProvider.write(key, version, content)
+			.then(null, error => Promise.reject(new RemoteUserDataError(error.message, toUserDataErrorCode(error))));
 	}
 
 }
diff --git a/src/vs/workbench/services/userData/common/settingsSync.ts b/src/vs/workbench/services/userData/common/settingsSync.ts
index b59afff1b52..5a9cb0556d4 100644
--- a/src/vs/workbench/services/userData/common/settingsSync.ts
+++ b/src/vs/workbench/services/userData/common/settingsSync.ts
@@ -374,7 +374,7 @@ export class SettingsSyncService extends Disposable implements ISettingsSyncServ
 		try {
 			await this.remoteUserDataService.write(SettingsSyncService.EXTERNAL_USER_DATA_SETTINGS_KEY, userData.version, userData.content);
 		} catch (e) {
-			if (e instanceof RemoteUserDataError && e.code === RemoteUserDataErrorCode.InvalidVersion) {
+			if (e instanceof RemoteUserDataError && e.code === RemoteUserDataErrorCode.VersionExists) {
 				// Rejected as there is a new version. Sync again
 				return this.sync();
 			}
diff --git a/src/vs/workbench/services/userData/common/userData.ts b/src/vs/workbench/services/userData/common/userData.ts
index 10ac85fdf93..62babe33d35 100644
--- a/src/vs/workbench/services/userData/common/userData.ts
+++ b/src/vs/workbench/services/userData/common/userData.ts
@@ -12,7 +12,40 @@ export interface IUserData {
 }
 
 export enum RemoteUserDataErrorCode {
-	InvalidVersion = 'InvalidVersion'
+	VersionExists = 'VersionExists',
+	Unknown = 'Unknown'
+}
+
+export function markAsUserDataError(error: Error, code: RemoteUserDataErrorCode): Error {
+	error.name = code ? `${code} (UserDataError)` : `UserDataError`;
+
+	return error;
+}
+
+export function toUserDataErrorCode(error: Error | undefined | null): RemoteUserDataErrorCode {
+
+	// Guard against abuse
+	if (!error) {
+		return RemoteUserDataErrorCode.Unknown;
+	}
+
+	// FileSystemProviderError comes with the code
+	if (error instanceof RemoteUserDataError) {
+		return error.code;
+	}
+
+	// Any other error, check for name match by assuming that the error
+	// went through the markAsFileSystemProviderError() method
+	const match = /^(.+) \(UserDataError\)$/.exec(error.name);
+	if (!match) {
+		return RemoteUserDataErrorCode.Unknown;
+	}
+
+	switch (match[1]) {
+		case RemoteUserDataErrorCode.VersionExists: return RemoteUserDataErrorCode.VersionExists;
+	}
+
+	return RemoteUserDataErrorCode.Unknown;
 }
 
 export class RemoteUserDataError extends Error {