Hey, I found the fix!
For some reason, it’s some weird issue with the OneDrive and Documents folders.
Try this:
You have to open RegEdit and go here: HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders
Find these two things, and change their location to just have OneDrive removed. It should look like this afterwards.
When you’re done, restart your PC, and then find “documents” in your windows explorer. Right click it, then hit “properties” and then “location”, and make sure it matches up with what you just did by hitting “restore default”. Hit apply and follow the steps. Afterwards, verify Fortnite’s files! It finally will open!!