Delete the .lck files in the directory you are storing your books.
(presuming you know for a *fact*, that the data files aren’t already open in
GnuCash but you just don’t see the window)
You should then be able to then open any data file.
You could also choose ‘Open-Anyway’ with the same
I have a windows 10 laptop. Today I got this message when I opened my file.
I have 3 different files on this computer and they all say the same thing. It
will not allow any backups so anything I did today is gone.
I tried older files and the same thing happened.
I tried my backups that were
