I found it out the prob. I was meaning to update this
Obvious... cause the path is shown the the plugin scan window (Donut, I'm a)
I have Acid 9 installed too, Acid 8 not working even after a re-scan. But directed it to
ProgramData > Magix > 9.0 (I think, you need hidden folders visible)
Anyway now Acid 9 plugins running in Acid 8, the Acid 8 ones must be corrupt somehow, prob need to download them again, but theres no point now I guess