Installer produces MaintenanceTool.exe.new

After installing our application on a system, the installer does not created a proper executable, instead the MaintenanceTool is named:"MaintenanceTool.exe.new"

What can be the reason? How to fix it?

Admin rights are available. But on the system are a lot of policies set, we don't know which one might be responsible to disable the renaming.

The only error message in the log is:

[135004] Critical: QWindowsPipeWriter: GetOverlappedResult failed. (Kein Prozess ist am anderen Ende der Pipe.) translated into englisch: "No Process at the other end of the pipe"

On our test systems everything works fine.