hat was most certainly the problem. When set to use every cpu/core in the system, it can drag the system down heavily (which in my case - it did: QI was running so sluggish as to become unresponsive). I set QI back to use only 2 of my 4 cores for thumbnail building and now at least the system is usable when QI launches.
I am a bit confused by your answer.
The more cores and threads that are running, the faster the job gets done, and Qimage only works your computer when making a print file, or building cache files and thumbs.
I suspect insufficient resources, and/or other programs running in the background.
Qimage will build thumbs and cache for the number of shots in the current open folder. AND IT DOES THAT ONE TIME ONLY!
Even with 100 images to process, it only needs 3 or 4 minutes. After that, Qimage rests and does the menial chores of refine, edit, placement, etc.
fred