diff --git a/src/tsconfig.strictNullChecks.json b/src/tsconfig.strictNullChecks.json
index e31554b85e02a388ae65c5f486a136a412f51bd9..7cc1e5cbb6b3c2cad30b4ea7ab3730c50f4b1bf0 100644
--- a/src/tsconfig.strictNullChecks.json
+++ b/src/tsconfig.strictNullChecks.json
@@ -387,6 +387,8 @@
 		"./vs/workbench/services/decorations/browser/decorations.ts",
 		"./vs/workbench/services/decorations/browser/decorationsService.ts",
 		"./vs/workbench/services/decorations/test/browser/decorationsService.test.ts",
+		"./vs/workbench/services/dialogs/electron-browser/dialogService.ts",
+		"./vs/workbench/services/dialogs/electron-browser/remoteFileDialog.ts",
 		"./vs/workbench/services/editor/browser/codeEditorService.ts",
 		"./vs/workbench/services/editor/common/editorGroupsService.ts",
 		"./vs/workbench/services/editor/common/editorService.ts",
diff --git a/src/vs/workbench/services/dialogs/electron-browser/remoteFileDialog.ts b/src/vs/workbench/services/dialogs/electron-browser/remoteFileDialog.ts
index 299ac57f673fba3be4319c5f4a2491511d75297b..a777eca3268cc93602bfd283d92640f7191216e6 100644
--- a/src/vs/workbench/services/dialogs/electron-browser/remoteFileDialog.ts
+++ b/src/vs/workbench/services/dialogs/electron-browser/remoteFileDialog.ts
@@ -122,7 +122,7 @@ export class RemoteFileDialog {
 		let homedir: URI = options.defaultUri ? options.defaultUri : this.workspaceContextService.getWorkspace().folders[0].uri;
 		let trailing: string | undefined;
 		let stat: IFileStat | undefined;
-		let ext: string = resources.extname(options.defaultUri);
+		let ext: string = resources.extname(homedir);
 		if (options.defaultUri) {
 			try {
 				stat = await this.remoteFileService.resolveFile(options.defaultUri);