No it’s weird. Nothing happens? It doesn’t even bounce? I just keep clicking it on the desktop and in recents…buts it’s being stubborn and not doing anything,
Do you have multiple devices? Sometimes, the desktop is synced, to (iCloud settings)
If the file is opened on that other device as well, things go awry…)
I suspect this is a clue. If dropbox can’t access the file either, then the problem is with either your OS or the file itself, not with SketchUp. Have you tried rebooting the computer?