Disk activity periodically high from temp files that look like "2FQgISac.exe.part" and are signed by MS

Question

My computer is periodically bogged down by disk activity that I've tracked down to files of an usual type.

The symptom is that my computer UI bogs down (mouse stutters, UI buttons lag, etc).

While this is going on, in the Resource Monitor I can see high disk activity (the heavy disk use seems to be the source of the slow OS/UI). This whole situation happens only every once in a while. The files that Resource Mon lists as associated with the high level of disk activity are randomly named but always in the form "[letters/numbers].exe.part" and are located in my temp folder. One that I noticed today is 2FQgISac.exe.part. There seems to be only one of these files active at a time.

At first I thought it was a virus or something but I right clicked on the file in explorer and examined its properties -- it is a digitally signed file from Microsoft! So that rules out most of kind of viruses? Obviously I've googled for this but I can't find anything relevant.

Does anyone know what this is, whether there's a way to get it to stop bogging my user interface and/or any other thoughts or suggestions on how to get my computer back to normal? It seems like this issue has cropped up in the last 30 days for me and I've uninstalled any software I've put on the computer in that time but that hasn't helped..

Thanks for any assistance!