Do you see anything at all when the Scheduler exits? Or is it just disappearing? If so, looks like yet another Windows 10 "disappearing app" situation. I'll need to gather info. I'm trying to get a handle on what is "suddenly" causing these. It's looking like possibly a .NET Framework update. I tried calling on the -4744 number, but I got a FAX or ??

Since you can repro this, please do me a favor and gather some info for me. Right click on My Computer or whatever and select Manage. Then select System Tools > Event Viewer > Windows Logs > Application. In the top center window (which will take a long time to load!!) find any (all) events for the time you ran the test and check for ones that mention scheduler.exe. For each (there may be 2-3) double-Click that event's line, select the Details tab, and then click Copy. Open Notepad and paste the data into that, save it, zip it, and attach to a reply here. That info might provide a clue. I have one other of these now, from a Japanese system, and I want to get one from each system that this is happening to. I'm looking at the version number of 'mscorlib' DLL, the .NET runtime, which is where the other one of these is failing.

If you have a system/image backup from before this started happening, I would suggest you apply it and get your system back on its feet. Then stop Windows updates. Failing that force update your system to the present. I have a clean W10 1903 test system here that is totally up to date as of yesterday. ACP Expert is running fine on it, so that's why I can't repro this. I'm hoping to heck that they have repaired this and that updating to the present will get you going again. If not I will need to isolate the offending update, assuming I can reproduce it at all here. I don't know what it is nor what it might be dependent on.

This is my best efforts to help you. I'm afraid the root cause is beyond my area of knowledge and outside my capabilities.