At one or more a minute, new folders are created in Logged in User/appdata/temp. The folders names are 3 or 4 characters in length such as, 1eec or 3bc5, or 2d3f. Each folder contains a sub-folder "Appdata" among other things. As the number of folders increases in to the 1000s, the PC's performance degrades.
I cannot find any reference to any malware, etc. that describes this behavior. The folders can be easily and quickly deleted in Safe Mode. I ultimaley resolved this issue by going back to a restore point a couple of days prior to the infection.
Neither Symantec EndPoint 12.1.5, or Malwarebytes, or YAC found anything awry on this PC. However, Malwarebytes was reporting some "Malicious OUTBOUND activity".
Anybody have a clue what this was?