diff --git a/src/vs/vscode.proposed.d.ts b/src/vs/vscode.proposed.d.ts
index 22732054feb382fa7c2ac0c43ef990045df5c3ec..3fb6c394c417beb6c6e04933717f716b62a3b20b 100644
--- a/src/vs/vscode.proposed.d.ts
+++ b/src/vs/vscode.proposed.d.ts
@@ -147,7 +147,6 @@ declare module 'vscode' {
 	//#region Joh - read/write in chunks
 
 	export interface FileSystemProvider {
-		seperator?: '/' | '\\';
 		open?(resource: Uri, options: { create: boolean }): number | Thenable<number>;
 		close?(fd: number): void | Thenable<void>;
 		read?(fd: number, pos: number, data: Uint8Array, offset: number, length: number): number | Thenable<number>;