This has already happened once before. Throughout the projects that I work on, I save frequently and there is a loading bar at the bottom of the screen that shows my document has been saved. However, when I reopened Krita awhile later to fix something on my project my document isn't anywhere to be found. It isn't on the recent documents or in my krita file. Firstly I really like this program so I want to know if this is just a bug or something I can fix. Secondly, is there any way I can retrieve the most recently lost document because it is really important. Also I have a windows 10 laptop.

Checck whether https://docs.krita.org/en/KritaFAQ.html ... annot-save is relevant. We've seen other people complain of this issue, but never seen it ourselves.

What format dod you try to save into? Is there anything special about the directory you wanted to save? (eg. Dropbox, Googke Drive, different hard drive etc.) Do you have problems woth space on any of your disks (not only the one you tried to save into)?