Is the Finder Wobbly in Big Sur?
I’ve had some strange events in which my main working SSD sometimes vanishes from the Finder, although that external drive remains mounted normally.
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The first time that it happened, I assumed that the external SSD had somehow unmounted then remounted, although neither I nor any running software appeared to have done so. There are no notifications about such an event either. It appeared that the Finder had simply lost its place, lost my working folder from Favourites, and carried on without it.