TextEdit permission issue - cannot save changes
I have a TextEdit (.rtf) file that I update daily to track my work hours, and it keeps telling me I can't save because I don't have permission. The file info says I have permission, though it has a lock on it. Of course, I have unlocked the file in the Info window, but it still tells me that I don't have permission to save; even when info shows unlocked, it refuses to save. I've tried force-quitting and relaunching TextEdit (sometimes that works). I've tried saving a copy and then quitting (sometimes that works, but it's a pain). I've created a new file and trashed the old one more than once. Why is this file persisting in this behavior and how do I stop it? I'm running Big Sur OS11.3.1 but the problem existed in previous versions of OSX.
iMac 21.5″, macOS 11.3