Application crashes in Windows 10

[vuke15]

Application crashes after some time in Windows 10.
.NET error it seems, even if framework 4.8.04084 installed

Application: StayFocused.exer
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.ArgumentException
at System.Diagnostics.Process.GetProcessById(Int32, System.String)
at StayFocused.WindowWatcher.OnWinEvent(IntPtr, UInt32, IntPtr, Int32, Int32, UInt32, UInt32)

Faulting application name: StayFocused.exe, version: 1.0.0.0, time stamp: 0x5fb42e9c
Faulting module name: KERNELBASE.dll, version: 10.0.19041.1202, time stamp: 0xc9db1934
Exception code: 0xe0434352
Fault offset: 0x0000000000034f99
Faulting process id: 0x74a4
Faulting application start time: 0x01d7c5eb5fa8c440
Faulting application path: C:\Users\vvv\Apps\StayFocusedBeta3\StayFocused.exe
Faulting module path: C:\WINDOWS\System32\KERNELBASE.dll
Report Id: ac421fe3-8d34-4c41-a7b9-aa23208bf3b7
Faulting package full name:
Faulting package-relative application ID: