den Hello, what does this error mean, and how to fix? After upgrade some of my sheets return this error.
den This error shows for sheets that older than a year or 2. All old sheets (and some newer ones) are now inaccessible. This is a major problem as backups are now also useless and data is inacessible.
den For those struggling with this problem, thanks to @hirsebrei solution a few posts lower than this, I have now fixed this.
