I’ve been using Visual Studio on Mac quite a lot recently, and it’s always updating itself – a lot more often than I’d like to be honest – but almost every-time it updates, when I load my project I’m greeted with a screen full of red squiggles from Intellisense.
It seems that on my system the old cache files are not purged and there is a mismatch that makes Intellisense go crazy. The code still compiles and runs, but it’s hard to work with.
For me, the fix I’ve found has been to just dump the cache folder into the trashcan & re-launch Visual Studio.
For anyone wanting to do this, just navigate to your ~/Library folder, then Caches, and finally scroll down to the Visual Studio folder there. Just dump that entire folder in the trash and Intellisense will be much happier when you restart.