I was having this issue with one of the accounts on our family PC. OneDrive worked for all the other users.
I uninstalled and installed OneDrive (don't do this if you have multiple accounts on a PC - you will have to reconfigure OneDrive on each account afterwards), and it doesn't fix the Loading issue. The reset suggested above didn't fix it either.
In the end, I tried something that I had initially thought of, but couldn't find the right Key in the registry when I looked the first time.
Please be very careful when making changes in the registry, I take no responsibility for any issues you may encounter through incorrect use of the registry editor.
Make sure OneDrive isn't running for any of the currently logged in users.
Open the Registry editor using regedit
Rename the Key Computer\HKEY_CURRENT_USER\Software\Microsoft\OneDrive to OneDrive.old
Restart OneDrive for your current user.
When you log in, it should work properly. At least it did for me.
If that doesn't fix it, quit OneDrive, delete the new OneDrive key that was created in the registry, and rename OneDrive.old back to OneDrive