[BetterRed]

I don't think they're from installs, I think they're from conversions - if you look inside the files in the folders you'll see stuff you recognise. Only some conversions leave stuff behind in the session temp folders, I can't recall any of them crashing or me killing them - its probably a timing issue or as Kovid suggests your AV - I would advise against excluding temp folders from your AV.

Calibre's just one of many programs that 'leaves' files in my Temp folder.

Once week, after closing all applications including those run in the tray, I run the Windows Disk Clean utility.

Anything that's in Temp is fair game for deletion, you can't delete everything in there if Windows is running - Disk Clean will bypass those files, if you tick the boxes it will also clean up browser caches and empty your trash etc.

BR