I see some items in Finder show up as bold and I wonder what that means. The example I have attached is somewhere under ~/Library. It's the most recent place I've seen this, not the only place. It also happens outside of ~/ and its subdirectories. It looks like a feature more than a bug. I wondered if it had to do with Git (maybe MacOS High Sierra shows Git statuses in Finder by default the way Ubuntu does), but no. I wondered if it's a Time Machine thing too (i.e. files not yet backed up may be shown in bold). I don't have a definitive answer. I haven't seen this advertised as a feature anywhere on Apple's site or any similar questions in Apple's support site. If this is a feature, I'd really like to know what it's for.
Thanks!
Best Answer
It makes it bold when the file name is truncated due to lack of space. If you move the horizontal bar to the right to see the full name it will un-bold.