Hi LeVarnM, I think you mean MacOS (iOS is for iPhone/iPad). I'll flag your question to move it to the Firefox for Desktop forum. Meanwhile, one possible reason for that message is if the profile is locked by another process. If you haven't already, please try a regular shutdown and restart of your Mac to free up any file locks. Also, in case it didn't come up before, check this article: [[How to run Firefox when your profile is missing or inaccessible]].