While tracking down some 'lost' disk space, I just noticed quite a few older sessions in my CALIBRE_TEMP_DIR taking up close to gig:
1. Why does this happen? I'm suspecting from unexpected shutdowns (either Calibre or system; one of the dates I recognize as a power outage).
2. Is it safe to clear out older sessions while Calibre is running? I was thinking of making a scheduled task to empty out the folder contents every few days.