As above said, I did remove all data before delete Pro. it does not work.
I only have updraft for backup, it does not run this week. Also my hosting server does not backup this week, either.
Eventually, when I delete ajax search Pro, and recover disk from backup of 1 week ago. disk space go back to normal now. 5G space free up.
I dont mind paying money for decent plugin, but Pro does not really work for me, though it has some advanced function. I prefer Ajax Lite, basic function good enough for me.