Gibts hier irgend einen Kniff oder startet der Srv nur signierte Apps?
Nope, on the contrary, on Windows Server Editions the Digital Signature is a little more relaxed than the other Editions, the assumption is the
OS should be hardened enough and doesn't allow arbitrary users to run/install arbitrary software, these system managed by professionals as administrators.
Suggestion :
Use EurekaLog or Madshi to find and log a critical bug that your monitor have, most likely something to do with Windows Shell,
are you using exotic component(s) ?
and what about theming ?
Is there missed/mixed DLLs ?
Make sure you have logging facility (or the
exception tools i mentioned) and see where this application is stopping, did it run and crash or the
OS stopped it form running, because also that could be a policy, like a policy to prevent uploaded binary through RDP from running, these can go into quarantine waiting for Administrator to whitelist them.
Have a look at this from 2021
https://techcommunity.microsoft.com/...e/ba-p/2724685
This is very simple example, the search gave me this one as top (for some reason) on how Microsoft do introduce/change policies by default.