I use Xournal 0.4.5 for work with pdfs: adding comments, ticking, etc. I save files as pdf.xoj - standard Xournal format. There was no any problems with opening it and editing again.
My problem is that, yesterday I save one .xoj file [everything as usual] and now I can't open it because there is only message "Could not open background". I can open others files, but in the case of this one there is no such possibility.
I am trying with preferences editing, ticking and unticking various options but there is still the same.
Maybe anyone have any idea how to fix it?