Hi @Anonymous,
Welcome to the Fusion 360 Community!
Just to check - is there a file that is pending being saved? I just want to make sure that we don't lose any data! I do know that we can force a recovery file save if you press CMD+Shift+S, but let's make sure it saves successfully before exiting the software. Are you able to export the file at all (as a .f3d file for back up)?
Off of the top of my head, the bug that was present in the other post you posted in has been fixed (which might be why that workaround is not working). The only other thing I can think of is if the file is in Read Only mode or if you do not have a valid entitlement on your account. Do you see Read Only anywhere near the top of Fusion? Also, is this happening on all files, or just one? We can check the entitlement if you go to the About dialog from the Help menu in the top-right corner. What does it say next to Active Plan?
Quick question - are you able to toggle into offline mode and save there? I'm curious if switching the environments will trigger that message to go away.
Thanks,
James Youmatz
Product Insights Specialist for Fusion 360, Simulation, Generative Design