diff --git a/lib/xctest.js b/lib/xctest.js
index 315a055..ddbbab1 100644
--- a/lib/xctest.js
+++ b/lib/xctest.js
@@ -127,6 +127,7 @@ class Xctest {
         const appOptions = { StartSuspendedKey: false };
         if (majorVersion >= MAJOR_IOS_VERSION_12) {
             appOptions.ActivateSuspended = true;
+            appOptions.__ActivateSuspended = true;
         }
         const launchResult = await this._instrumentService.callChannel(PROCESS_CONTROL,
             'launchSuspendedProcessWithDevicePath:bundleIdentifier:environment:arguments:options:',