At the moment (June 2015) Microsoft has three sync engines in the market, two are a bit rubbish and they plan to have a single one by Christmas. The good one is the consumer version of OneDrive that can be downloaded and installed into Windows 7. This works brilliantly which in the case of sync engines means “as good as Dropbox”. The bad and ugly one is OneDrive for Business which works most of the time but is fragile. Here are my hints, Ne
ver copy large number of files (eg more than 100) into your OneDrive for Business folder with the sync engine running. It gets confused. Always “Pause syncing” and then “Resume syncing” after the copy is complete. If you are having issues then the menu may prompt you to “Repair” or resolve “Sync conflicts”. Fix sync conflicts if you can. “Repair” simply deletes all the local files and downloads them again from the server. This can take hours and many people report that it does not work for them. Microsoft do have a OneDrive for Business Sync Issues Troubleshooter. This has a “Fix it” that can check for and fix files with invalid file names. Many people report that sometimes nothing can fix their issues. A particular issue is that syncing never ends and says “1 file remaining”. In this case you may need to nuke the system and start again. To do this,
- Pause syncing
- Move all your files out of OneDrive for Business into safe local storage.
- Login to OneDrive for Business on the web and delete all your files
- You now have zero files on the PC and zero files in the cloud. Resume syncing and you should get the message “OneDrive – up to date”
- Pause syncing
- Move all your files from temporary storage back into OneDrive for Business
- Resume syncing
- Go away have a cup of tea and come back in a few hours and you should get “OneDrive – up to date”
This method take some time but is not particularly onerous. At step 4 you can optionally uninstall OneDrive for Business, reboot, and reinstall. This is more effort but guarantees that all caches are cleared.
–Update 2015-07-02–
I found that OneDrive for Business conflicted with Microsoft Security Essentials (MsMpEng) and the computer was locked at 100% CPU. After many hours trying to fix the problem I gave up and uninstalled Microsoft Security Essentials and replaced it with a minimum installation of Avast! Free. This seems to be working.
Dr James Bayley 
I was just able to resolve the “x files remaining” problem by navigating to the user’s local synced folders and finding the unsynced files by looking at the icon overlay, opening the files and closing them. There were two in my case.
Thanks Joe. I had a lot of problems on Windows 7. I have now been using Windows 10 for 6 months and have only had two or three issues. In both cases I solved them using your method.
James
Thanks for this. Your “1 File Remaining” trick worked like a charm.
Sometimes “1 file remaining” stay there for days. Sync process works (tested with new file in and out ) by “remaining file” cannot be identified (no red cross on it ). So .. what to do in this case ? No errors, no “sync problems” just 1 remaining …..
There is a new option when you right-click on the One Drive for Business icon in the system tray. Choose “Repair” and this should fix the problem.
This is true but sometimes its fix is simply to delete ALL your local files and then download them again. This is very traumatic if you have lots of data.
Hi,
I found only MS documents are not synced.
If you paused Microsoft Office Upload Center previously, resuming it syncs all files properly.
I have had the “one file remaining forever” on my Onedrive for Business but not been able to identify the file, until I noticed that if I open Outlook and try to attach a file I suddenly see the symbol showing which folder contains an unsynced file. I can the navigate to the file and cut and paste it to the desktop. Renaming it makes it possible to copy back to Onedriv and the file is synced.
This is the problem: “Sync icon overlays are missing from OneDrive for Business synced items”, and this is the Microsoft fix: https://support.microsoft.com/en-us/kb/3079213.
Thanks, this worked like a charm even though I have the normal OneDrive version which comes with Windows 10.
It does works, but the pain is where you have to do this every sync problem. Every week i have to click repair and solve problems by hand. I thought microsoft is the pioneer of cloud computing solution? what is this trickery? What happened to automation?
OneDrive is now rock solid. There are two components to the system. Windows 10 and the OneDrive Sync client. Both must be completely upto date. The OneDrive Sync client updates itself automatically every day. If you suspect it is corrupt you can reinstall it from here. https://go.microsoft.com/fwlink/?linkid=844652. If you suspect that you have some “bad” files then you should download and run the EasyFix tool from here. https://support.microsoft.com/en-us/help/2933738/restrictions-and-limitations-when-you-sync-sharepoint-libraries-to-you. Good luck