diff --git a/src/vs/workbench/api/node/apiCommands.ts b/src/vs/workbench/api/node/apiCommands.ts
index 9adcf231889..6be39d21aaa 100644
--- a/src/vs/workbench/api/node/apiCommands.ts
+++ b/src/vs/workbench/api/node/apiCommands.ts
@@ -49,8 +49,8 @@ export class OpenFolderAPICommand {
 			return executor.executeCommand('_files.pickFolderAndOpen', forceNewWindow);
 		}
 		if (!uri.scheme) {
-			console.warn('`vscode.openFolder` command invoked with an invalid URI (scheme missing): `${uri}`. Converted to a `file://` URI.');
-			uri = URI.file(uri.fsPath);
+			console.warn(`'vscode.openFolder' command invoked with an invalid URI (scheme missing): '${uri}'. Converted to a 'file://' URI.`);
+			uri = URI.file(uri.toString());
 		}
 
 		return executor.executeCommand('_files.windowOpen', [uri], forceNewWindow);