mat-debug-xxxx.log files

I never found a mat-debug-xxxxxx.log file 'in use' in my temp folder. Is that where you found it or was it dynamically existing in Process Explorer?

Judging from your finding that the problem was spawned by a Microsoft based application (most likely MS Office) in the windowsapps folder, and the way I successfully fixed it.  I would guess that a recent MS Office upgrade left some active file or garbage (that was supposed to be removed or did not apply to that version of Office) in an important location in memory that is not normally cleaned out, and the result was (attempted) dynamic logging of an error every 15 minutes by an error checking telemetry file.

Hello  ---  if you start cmd.exe as admin you can look into windowapps --   

I discovered that it was local bridge  by trying to delete the mat-debug files -- but it was inuse -- so I then use the process explorer to file out with process was using it 

does anyone what changed to now have these mat-debug  files multiply like rabbits??

This folder windowsapps under Programs folder is secured so I cannot see the localbridge.exe app. However, based on searching under this executable on Google, I do not see anybody indicating that it produces other than error messages.  How did you reach this conclusion?

Hello --- I found that the  process that I creating these files  is "localbridge.exe" which is in the windowsapps folder and has some connection to   "office hub" --- what is this? can it be turned off?

Running MSCONFIG.EXE worked for me.  Reboot the first time with "normal startup".

Hello -- What did you change in msconfig?  Thanks