Many of you may have seen this message pop up in the corner of your screen. It generally means that a file you have in your OneDrive has an invalid character in the name. (# and % are the most common characters that throw this error.) When you see it, click the box to get more information.
If you missed the box, or it’s not currently showing, find your OneDrive tray icon by clicking the little arrow next to your system tray, finding the OneDrive cloud (which will have a red X on it if you have sync problems), then right-click that OneDrive cloud and choosing to View sync problems.
Either way you go, you’ll end up with a list of files as shown below. This will tell you exactly why a file couldn’t be uploaded. Simply click one of the file names, and you’ll be taken directly to the folder where it lives.
As you can see, the documents will also have the same red X on them, indicating the sync issue. Simply rename the file (F2 or right-click and Rename) and the error will resolve itself.
The sync icon will turn blue, then green when the file has been fixed. Repeat the process for any other files with errors.