
Today I got the following message when trying to save: "Unable to create backup file". I then looked in File Explorer to discover that there was no .BAK file even though I had set the Auto Save to every 30 minutes and had been using/saving the file for a month.
So, despite being able to save the file until recently there was never a backup file ... yet when I have to abort the file and then re-open it I get a message asking if I want to load a saved version (which is usually a day old - therefore I lose the current day's input!)

The file has about 15 worksheets and no really fancy Functions, graphs, etc.
Any advice would be appreciated.