diff --git a/src/vs/platform/terminal/node/terminalProcess.ts b/src/vs/platform/terminal/node/terminalProcess.ts
index 2ecdba35..ed74ee2f 100644
--- a/src/vs/platform/terminal/node/terminalProcess.ts
+++ b/src/vs/platform/terminal/node/terminalProcess.ts
@@ -170,7 +170,7 @@ export class TerminalProcess extends Disposable implements ITerminalChildProcess
 			cols,
 			rows,
 			useConpty,
-			useConptyDll,
+			...(useConptyDll ? { useConptyDll } : {}) as IPtyForkOptions,
 			// This option will force conpty to not redraw the whole viewport on launch
 			conptyInheritCursor: useConpty && !!shellLaunchConfig.initialText
 		};
@@ -392,7 +392,7 @@ export class TerminalProcess extends Disposable implements ITerminalChildProcess
 			return;
 		}
 		// Don't throttle when using conpty.dll as it seems to have been fixed in later versions
-		if (this._ptyOptions.useConptyDll) {
+		if ((this._ptyOptions as any).useConptyDll) {
 			return;
 		}
 		// Use a loop to ensure multiple calls in a single interval space out