Some characters have special meanings when used in file names in OneDrive. If a file or folder you’re trying to upload to OneDrive contains any of the characters listed below, it may prevent files and folders from syncing. You will need to rename the file or folder to remove these characters before you upload it. To rename a file or folder in Windows, right click on it and choose Rename from the menu. To rename a file or folder on a Mac, select it and press the ‘return’ key.
” * : < > ? / \ |
~ (only invalid if it is at the beginning of the file or folder name)
In addition, the following names aren’t allowed for files or folders: AUX, PRN, NUL, CON, COM0, COM1, COM2, COM3, COM4, COM5, COM6, COM7, COM8, COM9, LPT0, LPT1, LPT2, LPT3, LPT4, LPT5, LPT6, LPT7, LPT8, LPT9.
Lastly, the entire path, including the file name, must contain fewer than 400 characters.