I saved a document that I created in libreoffice (backup copy was always turned off). The next day, my 19 page document was replaced with 294 pages of the pound symbol. How do I open the past saves of the document?
If you happen to save them on a cloud, they may very well be there in a trash type folder. If not, install a cloud just for such. Once install a cloud will have a folder on you drive, you can add folders under it, everything saved under these folders will be saved on your drive and on the cloud, with a backup on cloud! And on every other computer you install your personal cloud to! Meaning, 3 backups.
Unless you have a special strategy for saves (always changing the name), you can’t. OS file systems usually keep only one copy for a file name. Nowadays, file systems usually use a method called journalling to be more fault-tolerant. In this method, files are never overwritten but a brand new copy is created every time you save. Simply, a “pointer” is substituted in the file catalog when everything is ready on disk.
Eventually, you may try to look for some recovery utility which scan disks for lost files (undelete feature). If your disk is not too full, the stale sectors will not yet have been reused and your odds are good to succeed.
Note that the utility depends both on the OS and the specific file system on your disk.
If you want to begin saving all the different versions of your documents, you could try “version control software”, often used on large, complex development projects but might be adaptable to simpler situations. These programs save each new version with a serial number or time-stamp and information about who revised it, etc etc. Some of the programs are free. See this article
@v3oat: I thought of that (see Dument version management question) but standard format for saving documents is binary and VCSes will not handle the situation efficiently, i.e. they will record the whole file instead of diffs.
@ajlittoz : Thanks for that; I was not aware of the restriction. Very interesting discussion in your reference. (Actually, since an “unfortunate incident” many years ago, I no longer use incremental back-ups, so the “whole file” is OK for me.)