1. Check the Steam Data Folder: While sometimes the steam cloud can be the very thing to cause the issue, it might also be the very thing that ends up saving you. Navigate to C:\Program Files (x86)\Steam\userdata\STEAM ACCOUNT NUMBER\105600\remote (the steam account number is going to be a collection of random numbers and it will be different for each person. Most likely you will only see one folder so click whichever one shows up.) and see if your files are there.
2. Recover your files from the .bak files: Located in Terraria's default save location which is \Documents\My Games\Terraria you should see a worlds and player folder. Click on whichever folder that applies to you and see if there are any .bak files of your old or missing characters. Simply rename the file extension to .plr if it is a player file or .wld if it is a world file.
3. Revert to a previous version: Sometimes when your character or world gets corrupted the file remains in its respective default save folder but is simply unusable by the game. You can revert to an earlier version of the file so that you don't lose ALL your progress. Using this method some of your progress will still be lost. First navigate to either \Documents\My Games\Terraria\Worlds or \Documents\My Games\Terraria\Players depending on what kind of file was corrupted. Right click the file and select properties. Now select the "Previous Versions'' tab and see if anything is there. If so, select the version you wish to revert to, click it, and then click restore.
4.Recreating the character/world: These are 3rd party softwares not owned by Relogic but they are trusted and safe. In the event that all else has failed you can use an inventory editor to help remake your character or TEdit to help remake the world:
Remaking your character:
Terrasavr, web-based Terraria profile editor This one is web based and pretty simple to use If you’re having trouble figuring it out there’s a help button in the top right to help explain it’s various features
Remaking a world: This one is a bit more complicated, you are going to need the newest version of TEdit:
Releases · TEdit/Terraria-Map-Editor Simply copy the seed and get just the world file, load the file through TEdit, the app will likely inform you that it is corrupted and proceed. When a world is corrupt a chunk of it is missing from the world file like so:
(do not close TEdit in this process) When this is the case what you can do is use TEdits select tool (it’s a blue square located on the left side) and select part of the world that still exists, you will then want to create a new world using your old world’s seed and after that load that world up in TEdit, you will then go to your clipboard and paste in the old world’s layout over the new one. When highlighting your world you will want to go from the edge of where it breaks to the top of the world on the opposite side. Just paste the new one over and select the bosses you will have killed and click “Save” in the top left side. Delete your old world files and load up your new world.