Ok this was bizarre – we had a customer who had multiple machines where OneDrive for Business would not startup.

They swore that it was working fine. Never trust an end user.

The fix was to reverse a registry key which had disabled OneDrive, which in itself proves the users had no idea what they were talking about. Some administrator had rolled out a registry key to disable OneDrive, so there is no way it could have been working.

Always take what an end user tells you with a grain of salt. Like: a very very small grain.

Here was the fix to reverse the problem: Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\OneDrive.DisableFileSyncNGSC set value to 0

Reboot

You are welcome =)

This was so annoying – OneDrive would not sync this one stupid file on my machine.

I finally found the fix is to run an administrative command prompt and then run:

chkdsk /r /f

Reboot

Fixed!

Credit goes to “The IT Initiative” : https://www.youtube.com/watch?v=SMd2s1Em42Q

Yesterday 1/24/17, Microsoft announced (here) that the OneDrive Next Generation Sync Client (NGSC) which replaces the older Groove.exe sync client now supports syncing SharePoint Online document libraries (sorry, no NGSC for on-premises SharePoint).

First verify that the build number is 17.3.6743.1212

It is supposed to automatically update but you can also download it from: http://onedrive.com/download

If you were previously participating in the preview build so that you could test out this feature, you previously had to deploy a registry key called “TeamSitesPreview” to enable syncing SharePoint Team sites.

Now, as long as you have the client build 17.3.6743.1212, then the registry key is no longer necessary.

However, if you don’t have the registry key then you will need to change a brand new setting that just appeared in the SharePoint Online Admin Center called Sync Client for SharePoint.
As you can see in the screen shot below, the setting for ‘Sync Client for SharePoint’ defaults to ‘start the old client’.

Important: This needs to be changed to ‘start the new client.’

So if you don’t have access to your SharePoint tenant to change the default sync client for SharePoint to use the new client, you can use the registry key to override it locally on your system.

[HKEY_CURRENT_USER\SOFTWARE\Microsoft\OneDrive]

“TeamSiteSyncPreview”=dword:00000001

Tip: If you are in there modifying the tenant, you might as well change the “OneDrive Sync Button” is set to “Start the new client.”

These changes take several hours to propagate. To check that they’ve propagated, go to a SharePoint Online site and click Sync. In the browser dialog box that confirms the request to open a program, the “Program” should appear as “Microsoft OneDrive” and the “Address” should start with “odopen://”

Troubleshooting

If you see either the OneDrive Setup Wizard or a dialog box asking “Which library do you want to sync?” after clicking “Allow” in Internet Explorer, then see Known issues for instructions on how to enable SharePoint site setup in Internet Explorer. There is a known issue that is actively being investigated by Microsoft: If you are using Windows 7 and your SharePoint Online site is still using the classic UI rather than the new modern UI, then you will need to use Edge, Chrome or Firefox until the integration issue with Internet Explorer is resolved.

On a Mac, you may find that you need to perform these additional steps:

1. If you are currently using the OneDrive Mac Store app, you must first uninstall it before installing the latest build of the new OneDrive sync client.
   1. Open Finder and Search for “OneDrive.app” or “OneDriveDF.app” from “This Mac.”
   2. Move all returned items to the trash.
   3. Once you’ve removed the Mac Store app, you can install the preview build of the new OneDrive sync client.
2. Exit the new OneDrive sync client by clicking on the OneDrive cloud icon in the Menu bar and selecting Quit OneDrive.
3. Open a terminal window by using cmd+space and searching for “Terminal.”
4. Run the following commands:
5. Defaults write com.microsoft.OneDrive TeamSiteSyncPreview -bool True
6. Defaults write com.microsoft.OneDriveUpdate Tier Team
7. Killall cfprefsd
8. Restart the sync client and log in again if prompted.

Reference: https://support.office.com/en-us/article/Enable-users-to-sync-SharePoint-files-with-the-new-OneDrive-sync-client-22e1f635-fb89-49e0-a176-edab26f69614?ui=en-US&rs=en-US&ad=US

The current ODFB synchronization engine is based on groove.exe and msosync.exe.   If you see OneDrive.exe in your task manager, that is the consumer edition synchronization engine for Onedrive.

When OneDrive for Business is healthy, the icon in the task tray will not display a useful troubleshooting option “View synchronization problems”

However, as soon as you have a file that will not synchronize, this icon will indicate a yellow exclamation point.

The first troubleshooting step is to right-click this icon and select ‘View sync problems…’

This will usually tell you why the file will not synchronize. In this case, it was because the file name contained an unsupported character “#”. As of 9/15/2015, here is the list of unsupported characters: \ , / , : , * , ? , ” , < , > , | , # , %  (Reference MS KB 2933738). Also, files cannot begin with a period “.” or a “tilde “~”.  Note: In the MS KB article linked above, there is a “Fix it tool” that can rename invalid filenames automatically.
Note: Microsoft’s roadmap site, roadmap.office.com, lists that the # and % characters will eventually be supported. 

Another reason why a file may not migrate is if it exceeds 2GB, which is the current maximum file size. This is also on the roadmap to eventually increase to 10GB per file.

Other limitations:

• File names must be less than 256 characters
• Folder names must be less than 250 characters
• The combination of the Folder + Filename must be less than 250 characters
• The total number of files synchronized must be less than 20,000. Note: Microsoft has publically stated that they are working on increasing this in the next generation synchronization engine (currently in beta as of 9/15/2015).

Outlook PST files

Whereas PST files aren’t actively blocked by OneDrive for Business, syncing PST files that are in an open state isn’t supported. If you decide to sync PST files (for example, an archive PST file that you don’t load or view in Outlook), they can’t be in an open state at any time by any application while they’re in the OneDrive for Business sync folder. A PST file that’s connected to Outlook will be updated regularly and therefore if synchronized, can result in too much network traffic and growth of the Office File Cache on your local drive.

OneNote notebooks

Because OneNote notebooks have their own sync mechanism, they aren’t synced by the OneDrive for Business sync client. You can upload OneNote notebooks to a SharePoint Online page. However, they won’t sync with through the OneDrive for Business sync client application. Additionally, if you add a OneNote notebook to a local folder that syncs with SharePoint Online, the notebook won’t sync with the SharePoint site and may cause other sync errors within the local folder.

Open Files

This is a big one. If you create a file in your OneDrive synchronization library, and attempt to open that file before it finishes synchronizing, you will get an error message within the application.

Other Gotchas

If you plan on migrating user file shares to OneDrive for Business (using 3rd party software) then keep in mind that the total file share size for each individual user should be less than the available hard disk space on the end-user’s computer. Otherwise, when they attempt to synchronize it, then they will fail.   For example, the user may have a 32GB SSD drive on their Surface Pro tablet, and they may have 100GB of files on their file share. If that file share is migrated to ODFB, and the user clicks the Sync button in their ODFB folder, they will fill up their hard disk and synchronization will fail. It gets worse – I have observed behavior where you attempt to remove these files from the local hard drive, only to replicate that as a deletion task in ODFB. Fortunately, the files should be able to be recovered in the ODFB recycle bin.  For now, just be aware of this issue and wait for the next generation synchronization engine, which may have the ‘selective sync’ option where the end-user can select which folders to synchronize.

Troubleshooting Methodology

1. Check the ‘View synchronization errors’ first to see if the problem is simple to resolve

2. Self-help articles that solve common problems like those explained above are found (here) and (here). If it is not simple, then the next step is to clean the cache with this command:

“Groove.exe /clean ”

Note: DO NOT use the /ALL command as described in this article (here). This is pretty destructive as described in this article here:
https://support.microsoft.com/en-us/kb/982279

3. Navigate to the hidden cache folder and shift-delete all the files inside this folder (delete the files inside this folder but leave the OfficeFileCache folder intact)

C:\Users\%username%\AppData\Local\Microsoft\Office\15.0\OfficeFileCache\

Follow this forum post: https://community.office365.com/en-us/f/154/t/281017

as it lists which processes to stop and then delete the contents of this folder:

C:\Users\%username%\AppData\Local\Microsoft\Office\Spw

Last resort method

If the above does not fix it, here is the last resort method of fixing synchronization problems: 

1. Remove Office 2013 completely from the computer by using the fix it tool in the article: http://support.microsoft.com/kb/2739501. Then, the cache data and registry information can be removed automatically.

2. Clear all related windows credentials by running the following command in Command Prompt:

rundll32.exe keymgr.dll, KRShowKeyMgr

3. Reinstall the latest version of Office.

Disclaimer

I’m optimistic that many synchronization problems will be alleviated in the next generation synchronization engine due out in Q4 2015. Until then, hopefully the steps above will be helpful. Please note: this post is provided without warranty, and is for educational purposes only (use at your own risk –> always backup your files before performing any of these steps).