I've been working on a Minecraft world since early September 2019, backing up multiple copies along the way. I reset my PC and imported my most recent save, but on load, none of my builds appear. Like a fresh world. Any ideas how to fix this and what caused it?
Are you sure that you opened the world in the same version or newer than the one it was last loaded in? Because this sounds a lot like what happens when you downgrade a modern version (all chunks are reverted to their initial state when downgrading any version past 1.13; of course, while it was less dangerous in older versions, e.g. 1.12 to 1.11, you'll still have missing blocks, mobs, etc).
Yes, I made sure the version it was created in (1.14.4) was the one used to load it, with the same issue. I have around 15 backups, none of them work. I wonder if the file transfer to the service I was using (MEGA) corrupted some of the files. I'm not sure what to do.
You could try getting help in the following thread to see if the backups can be restored in any way (one other thought - do these backups contain an entire world folder or just a level.dat file? I've seen this happen before where somebody thought level.dat contained all the world data - there should also be a "region" folder containing ".mca" files, which contain the actual chunk data):