Some Fab Filter plugins disappeared from WL9

I was using the plugins over the weekend. When I went to do a mastering session yesterday three of the Fab Filter Plugins were simply not there. It was easy enough to reinstall them but wondering why they disappeared? Also one of my favorite plugins the VST Stereo Tool was all of a sudden not authorized. No changes to the computer and no one else had used it. Anyone else have this problem or know why it may have happened? Thanks in advance.

<This was on a PC running Windows 7 Pro>

My RX 4 De Noiser plugin also got put in the “do not use” list but it was working fine last week. 9.0.35 seems to have some strange problems. 9.0.25 seemed more stable. How can a plug in get put into the “do not use” listing? I erased all the “do not use” plug-ins and had WL rescan the plugins the next time I opened it and the De Noiser plugin loaded up fine. I really do not need to be worried about plugins with the amount of work we have to get done.

How can a plug in get put into the “do not use” listing?

Never done automatically. At some stage, WaveLab asked you for a confirmation.