Permissions

[socrates-beach]

I just started getting this error message:
Changed notes could not be saved because your account lacks permission to access the directory.
I've been using nValt for about a year and it has been working fine. I synch with Simplenote and that works well. The odd thing is that despite the error messages all changes are being saved to the notes in Simplenote and my Mac. I'm using Mac OS Big Sur 11.2.3. I am also synching from an Apple Macbook Air and that laptop doesn't get the error. I've checked the permissions and they are the same.