I've been working on a peace for about 20-22 hours now and i went to open it one day and a pop up came up saying "this files cant be opened because it is a invalid file - reason .kra is not a supported file"

is there anyway to revert to a old save or is there a auto backup system?

I'm more then happy to give files if needed

thanks,
Atreyu

How autosave and backup system works: https://docs.krita.org/en/user_manual/autosave.html

Also which version are you using? Krita 4.2.0-4.2.7 had some... ummm misunderstandings with Windows (aka Krita trusted that files that are saved are actually saved when it asked Windows to do it), but Krita 4.2.8 and Krita 4.2.9 beta version should not have this issue: https://docs.krita.org/en/KritaFAQ.html ... le-anymore

Some other options for you to try to recover the files: https://docs.krita.org/en/KritaFAQ.html ... r-my-files

thank you,
i am having a little trouble recovering the files, i am using a older version at the moment I'm currently on 4.1.5 (I know I need to update)

do u know any other ways.
I'm sorry if this becomes annoying

thanks again,
atreyu