diff --git a/src/vs/base/common/uri.ts b/src/vs/base/common/uri.ts
index ec6497ef0b6fc07b409a82de422b93a19d32abdd..a55224af59e5ae1facc88fae3868b3d801aa9fbf 100644
--- a/src/vs/base/common/uri.ts
+++ b/src/vs/base/common/uri.ts
@@ -384,8 +384,8 @@ export class URI implements UriComponents {
 			return data;
 		} else {
 			const result = new _URI(data);
-			result._fsPath = (<UriState>data).fsPath;
 			result._formatted = (<UriState>data).external;
+			result._fsPath = (<UriState>data).fsPathBsl === (isWindows || undefined) ? (<UriState>data).fsPath : null;
 			return result;
 		}
 	}
@@ -401,8 +401,9 @@ export interface UriComponents {
 
 interface UriState extends UriComponents {
 	$mid: number;
-	fsPath: string;
 	external: string;
+	fsPath: string;
+	fsPathBsl: true | undefined;
 }
 
 
@@ -438,6 +439,7 @@ class _URI extends URI {
 		// cached state
 		if (this._fsPath) {
 			res.fsPath = this._fsPath;
+			res.fsPathBsl = isWindows || undefined;
 		}
 		if (this._formatted) {
 			res.external = this._formatted;
diff --git a/src/vs/workbench/test/electron-browser/api/extHostTypes.test.ts b/src/vs/workbench/test/electron-browser/api/extHostTypes.test.ts
index 56517bdd73c21d8ace9255ffc2e5e7987571a2e5..d69ac0f3fc3f2c3e3f3b797804acdb1b8003457a 100644
--- a/src/vs/workbench/test/electron-browser/api/extHostTypes.test.ts
+++ b/src/vs/workbench/test/electron-browser/api/extHostTypes.test.ts
@@ -31,6 +31,7 @@ suite('ExtHostTypes', function () {
 			scheme: 'file',
 			path: '/path/test.file',
 			fsPath: '/path/test.file'.replace(/\//g, isWindows ? '\\' : '/'),
+			fsPathBsl: isWindows || undefined,
 		});
 
 		assert.ok(uri.toString());
@@ -39,6 +40,7 @@ suite('ExtHostTypes', function () {
 			scheme: 'file',
 			path: '/path/test.file',
 			fsPath: '/path/test.file'.replace(/\//g, isWindows ? '\\' : '/'),
+			fsPathBsl: isWindows || undefined,
 			external: 'file:///path/test.file'
 		});
 	});