OneDrive for business is the preferred online storage service that comes with Microsoft Office 365, OneDrive is powered by SharePoint online and unlike the consumer OneDrive service can cause issues synchronising when using files with invalid characters or folders with unsupported names (more info)
If you are in a situation where OneDrive for Business will not sync or has stopped syncing these are the steps you should follow to resolve the issue.
1. Close and save any documents you are working on including all Office applications (Word, Excel, Outlook etc.)
2. Right click on the OneDrive for Business icon in the task tray
3. From the OneDrive for Business menu select repair (in most cases this will resolve the issue after a few moments)
Repair does the following:
- Disconnects all libraries that were experiencing sync problems.
- Reconnects these libraries. This means Repair downloads and syncs the current server version of each library, as if you were syncing for the first time.
- Creates an archive copy of any file that had unsynced changes and places these files in a library folder under C:\users\username\OneDrive for Business archives\.
If you change where your synced folders are stored, the archive folder may be called \OneDrive for Business — Unsynced Changes\ when viewed in Explorer. At a CMD or DOS prompt, the folder is called ODBA. In that folder, OneDrive for Business creates subfolders with the current date and time as the folder name, such as \2016-02-16 15-03-09\ to store files that can’t be synced.
When Repair runs, it syncs the folder with the files that aren’t causing the problems, and moves the other files into the archive. Repair creates these archive copies in case you had updates that couldn’t be synced to the server before you started Repair. This ensures that you don’t lose any local updates. You can compare file versions in the archive library folder with the reconnected folder to make sure you have the version you want.
When you’re done with repair, the notification icon that signals sync problems should be clear.
4. If the issue persist right clock the OneDrive for Business icon again and choose “View Sync Problems” This will open another window showing a list of files and folders that are not Syncing, double click on each of the entries and correct the issue or move the files to another location. Rename the files with valid names and check that the are not larger than the allowed limits.
Microsoft offer further guidance here or if you prefer help with these issues we offer an office 365 managed support contract for business customers and would be happy to help.