Origin Game Repair Takes A Long Time - What's Changed??

I had this problem too: the error; the incredibly extended time it took; the neverending finalizing; CPU usage 100%; packs being reiterated in repair cue.

I tried several things, but what 'solved' it, that is, what makes the repair go through in a couple of minutes with no hickups or errors; was to shut down my computer protection completely, then repair, then start protection again. Origin is shifty..