MSFS is no longer working

Greetings.
I installed new AV program and this piece of software identified Fenix a320 as a threat and removed it. After that I cannot start MSFS anymore. I am getting this message:

I tried to repair Xbox but it did not help. When I start MSFS I see white screen and then it crashes. Is there anything I can do before I will do a full reinstall.
Thanks for looking.

Did you remove / disable the new AV before doing the repair to ensure it isn’t just removing stuff again?

I did. No luck.