Corrupt catalog repeatedly
I have a corrupt catalog in Lightroom, have copied a recent back up, pasted in Lr folder and it opens, but when i click on another folder within Lr-- I get the error that it is corrupted and I can't use it. Mac OS Sierra 10.12.6 CC Lightroom, all up to date. I have had similar problems about 3 times in the last 3 months. Help please