Hello,
Sorry to hear you are having issues. First, please try, uninstall Start11, reboot immediately (important), download latest version available in your account product download page: https://store.stardock.com/myaccount/products. Install it, reboot immediately again. Retest it and report back.

If the issue still appear, report back with few more details.

1. Windows 10/11 full version and OS Build number. Use Winver.exe to get these numbers.
2. Start11 version you're trying to activate.
3. Any other details to help us understand the issue.

Thank you,
Basj,
Stardock Community Assistant.

Just as a test, try activate it in Sandbox mode, does the activation work while in there? Refer here for Sandbox Test: https://support.stardock.com/space/SHC/1416855562/Testing+Start+in+Sandbox. Try it and report back.

Thank you,

Basj,
Stardock Community Assistant

If the sandbox is working, that means something is interacting with that window to cause the issue...do you have any apps installed that augment the UI in any way? 

Try installing while in a new admin account, something as mention in a Clean boot steps : https://support.stardock.com/space/SHC/1334935592/Start11+Clean+Boot. Try it and report back. If that work, log out and log in again into your original admin account, does Fences still activated and work as it should?

Thank you,

Basj,
Stardock Community Assistant

Did this occur when you had the Start11 activation prompt occurring on a secondary display that had a different resolution than your primary?

I would love to be able to reproduce this so that we can isolate and fix the bug.

Hello, just wondering, you was using what resolution when the issue appear? And your monitor is by default at what resolution? 

Thank you,

Basj,
Stardock Community Assistant