diff --git a/src/vs/workbench/api/common/extHostDebugService.ts b/src/vs/workbench/api/common/extHostDebugService.ts
index 94132fed5b8..72b1bb63bc7 100644
--- a/src/vs/workbench/api/common/extHostDebugService.ts
+++ b/src/vs/workbench/api/common/extHostDebugService.ts
@@ -985,7 +985,7 @@ export class ExtHostVariableResolverService extends AbstractVariableResolverServ
 			getWorkspaceFolderCount: (): number => {
 				return folders.length;
 			},
-			getConfigurationValue: (folderUri: URI, section: string): string | undefined => {
+			getConfigurationValue: (folderUri: URI | undefined, section: string): string | undefined => {
 				return configurationService.getConfiguration(undefined, folderUri).get<string>(section);
 			},
 			getExecPath: (): string | undefined => {
diff --git a/src/vs/workbench/services/configurationResolver/browser/configurationResolverService.ts b/src/vs/workbench/services/configurationResolver/browser/configurationResolverService.ts
index 42b3431dc41..0343dc63dd8 100644
--- a/src/vs/workbench/services/configurationResolver/browser/configurationResolverService.ts
+++ b/src/vs/workbench/services/configurationResolver/browser/configurationResolverService.ts
@@ -44,7 +44,7 @@ export abstract class BaseConfigurationResolverService extends AbstractVariableR
 			getWorkspaceFolderCount: (): number => {
 				return workspaceContextService.getWorkspace().folders.length;
 			},
-			getConfigurationValue: (folderUri: uri, suffix: string): string | undefined => {
+			getConfigurationValue: (folderUri: uri | undefined, suffix: string): string | undefined => {
 				return configurationService.getValue<string>(suffix, folderUri ? { resource: folderUri } : {});
 			},
 			getExecPath: (): string | undefined => {
diff --git a/src/vs/workbench/services/configurationResolver/common/variableResolver.ts b/src/vs/workbench/services/configurationResolver/common/variableResolver.ts
index c29a083e759..1b832ff39d2 100644
--- a/src/vs/workbench/services/configurationResolver/common/variableResolver.ts
+++ b/src/vs/workbench/services/configurationResolver/common/variableResolver.ts
@@ -18,7 +18,7 @@ import { IWorkspaceFolder } from 'vs/platform/workspace/common/workspace';
 export interface IVariableResolveContext {
 	getFolderUri(folderName: string): uri | undefined;
 	getWorkspaceFolderCount(): number;
-	getConfigurationValue(folderUri: uri, section: string): string | undefined;
+	getConfigurationValue(folderUri: uri | undefined, section: string): string | undefined;
 	getExecPath(): string | undefined;
 	getFilePath(): string | undefined;
 	getSelectedText(): string | undefined;
@@ -162,9 +162,9 @@ export class AbstractVariableResolverService implements IConfigurationResolverSe
 		};
 
 		// common error handling for all variables that require an open folder and accept a folder name argument
-		const getFolderUri = (withArg = true): uri => {
+		const getFolderUri = (): uri => {
 
-			if (withArg && argument) {
+			if (argument) {
 				const folder = this._context.getFolderUri(argument);
 				if (folder) {
 					return folder;
@@ -200,7 +200,7 @@ export class AbstractVariableResolverService implements IConfigurationResolverSe
 
 			case 'config':
 				if (argument) {
-					const config = this._context.getConfigurationValue(getFolderUri(false), argument);
+					const config = this._context.getConfigurationValue(folderUri, argument);
 					if (types.isUndefinedOrNull(config)) {
 						throw new Error(localize('configNotFound', "'{0}' can not be resolved because setting '{1}' not found.", match, argument));
 					}
diff --git a/src/vs/workbench/services/configurationResolver/test/electron-browser/configurationResolverService.test.ts b/src/vs/workbench/services/configurationResolver/test/electron-browser/configurationResolverService.test.ts
index 9d1f709f55c..f616e92e6ee 100644
--- a/src/vs/workbench/services/configurationResolver/test/electron-browser/configurationResolverService.test.ts
+++ b/src/vs/workbench/services/configurationResolver/test/electron-browser/configurationResolverService.test.ts
@@ -206,6 +206,17 @@ suite('Configuration Resolver Service', () => {
 		assert.strictEqual(service.resolve(workspace, 'abc ${config:editor.fontFamily} xyz'), 'abc foo xyz');
 	});
 
+	test('substitute configuration variable with undefined workspace folder', () => {
+		let configurationService: IConfigurationService = new TestConfigurationService({
+			editor: {
+				fontFamily: 'foo'
+			}
+		});
+
+		let service = new TestConfigurationResolverService({ getExecPath: () => undefined }, environmentService.userEnv, new TestEditorServiceWithActiveEditor(), configurationService, mockCommandService, new TestContextService(), quickInputService);
+		assert.strictEqual(service.resolve(undefined, 'abc ${config:editor.fontFamily} xyz'), 'abc foo xyz');
+	});
+
 	test('substitute many configuration variables', () => {
 		let configurationService: IConfigurationService;
 		configurationService = new TestConfigurationService({