I'd just like to remind everyone how important it is to back up both Player and World files reguarly. This is also useful if you accidentally delete a world or player, and you didn't mean to... I did this with my main world once. To back up your files, do the following.
- On Windows 7, go to C:\Users\username\Documents\My Games\Terraria. The folder may be hidden. If not, skip to step 3. If you're running a previous version of Windows, go to C:\Documents and Settings\username\My Documents\My Games\Terraria.
- If it is, press Alt while in Windows Explorer. A bar will appear near the top of the window. Click Tools > Folder Options > View > and check the box by Show hidden files, folders, and drives.
- Copy both the Players and Worlds folders, and place them in a secure location.
- Create a new folder for each new backup, titled by date. This is in case you accidentally save a corrupted file to your backups, and delete an old non-corrupted version. Backups take up about 100mb each, depending on world size and other factors, so you may want to keep only the latest five backups. Whatever works for you.
If you do lose a world, simply copy the backup file (example: world2.wld) back to its original location. Terraria makes its own backups, titled similarly with the .bak extension, but this shouldn't be relied upon. This feature is totally useless if you accidentally delete a world or player yourself, as the .bak is deleted as well.
Corruption rarely happens after 1.1.1, but it still happens. It's better to be safe than sorry.