Hi i had the same problem and i have a possible temporary fix.
Try to clear the console by clicking on the console tab or go window>layouts>revert factory layout
Necropost here but anyway, just wanted to WARN you all about sometthing @RelativeTime said!
Reimport all will take a ton of time to complete even if your project might not be that “big”, so please before doing that think if it isn’t actually faster to restart unity