here is the fix
I stumbled on this solution, which in a nutshell – I had to delete over 131,000 temp files in the system32 folder. The users PC had built up 65,536 files named SETxxx.TMP and another 65,536 files name OLDxxx.TMP, all of them had some hexidecimal suffix (xxx) and when it reached 65,536 it stopped the ability to add HP printers. Each SET file was 497 KB and the OLD files were 0 KB. The total was 31.0 GB worth of junk!