Learn How OneDrive Sync Works With Office 2016

Stephen Rose

For years, you have been able to sync your OneDrive (and SharePoint) documents to your PC, which lets you work on the go while still being able to collaborate with others in Office. This integration was powered by the previous generation OneDrive for Business sync client (groove.exe), and we've been working hard to fix issues and improve reliability so the experience is as smooth as possible. With the release of the latest OneDrive sync client (which we refer to as the Next Gen Sync Client or NGSC, we saw an opportunity make the Office sync experience better than ever.

We've now delivered a new integration which combines the rock-solid performance and reliability of OneDrive with the advanced collaboration features of Office 2016. Here's a summary of how the latest OneDrive sync works differently from both competitors and from our previous sync client (groove.exe):


Office files always open from the locally synced file first

If a document is synced to your machine, Office will never wait to open the server copy. Office opens the locally synced file immediately, and if there are any changes on the server, Office will download those asynchronously. This allows you to open under any network conditions without waiting and is a big advantage over other sync and share services. Due to the partnership between OneDrive and Office, it doesn't matter if the file was opened from Recent Files, File Explorer, clicking a URL, etc. If the file is synced to the device, the synced file opens first.


Office files always save to the locally synced file first

Similar to how Office opens files, saves start with the locally synced file. After the file saves, Office will upload changes directly to the server. If Office can't upload because the device is offline, you can keep working offline or close the file. Office will continue to save to the locally synced file, and OneDrive will handle the upload once the device gets back online. In this integration, Office works directly with the files that are currently open, enabling co-authoring in Office apps like Word on the desktop, which no competitor offers. For files that are not open in Office, OneDrive handles all syncing. This is the key difference between the old sync client integration and the NGSC, and this lets us achieve co-authoring along with the best  performance and sync reliability.


Office uploads are efficient

Since the release of Office 2010, files are uploaded to  OneDrive via the MS-FSSHTTP protocol. This lets Office avoid uploading the entire file on every save if only a small part has changed. For example, if a PowerPoint presentation has a large video in it, that video won’t be re-uploaded on each save. It is much more efficient than a full file upload, and it again speaks to the tight interoperability between Office and OneDrive.  


Conflict Resolution

Some conflicts are unavoidable, and OneDrive gives you control over how these conflicts get resolved. If Office 2016 is not installed, OneDrive will create a second file with the user’s conflicting copy after detecting a conflict. If Office 2016 is installed, users have the option to “Open in Office” to resolve the conflict. This will either automatically merge the conflicting copies or show a merge experience that lets users pick the right version of each conflicting change. Users can choose to duplicate the file instead, or they can disable the “Open in Office” option entirely in the OneDrive settings.



Office 2016 and OneDrive work seamlessly together to keep your files in sync while letting you easily collaborate on your documents and share them with others. This integration provides dramatically improved performance and reliability without sacrificing advanced collaboration features like real-time co-authoring. Now you have a single tool to sync all your OneDrive and SharePoint Online content with the best integration with Office, great performance, and rock-solid sync.



Office integration with the OneDrive Next Generation Sync Client is available now for all Windows releases of Office 2016, and it works for all modern Office document formats (docx, xlsx, pptx, etc) synced by the Next Gen Sync Client. We’re also working to bring this experience to Office 2016 for Mac, though we don’t have a release date to share at this time.

Office integration with NGSC Teamsite sync requires click-to-run build 16.0.7167.2001+ or MSI build 16.0.4432.1000+

Eric O'Brien- Program Manager- OneDrive

36 Replies
Wow, this is awesome!!!

Great Info thanks!

Nice, I installed the client. Seems to work great. Different syncs (SharePoint, OneDrive, Group and schred folder) are running now. I hope it proves it's stability in the upcoming days.

Unfortunately, this isn't working for me. The OneDrive client warns me it couldn't merge the changes in two files, and gives me the option to open them in Office so I can review and merge the changes. When I click to resolve the issue, the files open in their respective application (Word or Powerpoint), but there aren't any pending changes to be merged.

And it is still running fine.
Really good to see this, thanks!

This is a great summary!  I am in an organization with two domains under seperate O365 subscriptions (x.com and y.com).  I have shared document libraries from SharePoint from x.com with y.com members.  y.com members can see all libraries in a browser.  However, the system will not allow y.com members to sync these libraries.  There are no domain resrtictions in the Admin console.  Should this be possible?

Was there a recent change? I was using the new protocal a few weeks ago to sync a SharePoint Online document library. Now when I synch a different library, it uses the groove protocal and opens OneDrive for Business instead of the new OneDrive client.

No changes from our end. Let me forward this to engineering.


Thanks for the heads up


There are two issues with this.  One is that the groove client might not have been disabled when the new client was installed.  You can run "%localappdata%\Microsoft\OneDrive\OneDrive.exe /takeover​" from the command line to ensure the new OneDrive for Business sync client is running.


The second issue is that the SharePoint Admin needs to select which sync client will be 'called' by SharePoint when users hit the sync button.  This is in the SharePoint Admin tool under settings:



One work around for issue two is to add the library from OneDrive in the taskbar by using the URL.

Hi Ward - Could you clarify the work around for issue 2? Are you adding the URL to the SharePoint Library to OneDrive??
In the Groove sync client, you can add a SharePoint folder to sync by pasting the URL into the pop-up that displays after selecting "Sync a new library" from the right-click dialog of the task bar icon. With the new sync client, you have to add folders by navigating to the SharePoint or OneDrive site and click Sync. The SharePoint or OneDrive admins have to change the SharePoint and OneDrive settings to open the new sync client to add the folder. The default setting is to open the groove sync client.

Hi @Stephen Rose - we've just finished doing some network traces on the sync client because of some performance issues.  What we are seeing doesn't quite line up with the description you posted here - so am interested in your thoughts.

Specifically, when the option "Use Office 2016 to sync Office files that I open" is selected, we see that when opening an Office document that it will always try to download the server version - even if there is a local copy available.  When the PC is offline, opening an Office document will wait and time-out before opening the local copy.

When we unselect the "Use Office 2016 to sync Office files that I open" option, it does indeed open the files from the local drive as expected.


So my questions are:

(1) - Is this by design?

(2) - What are the downsides of removing this default option to use Office 2016 to sync files?


P.S. I'm happy to share our network traces if that'll be helpful in explaining the behavior we are seeing.

@Eric O'Brien

I have an issue with the new generation syncing with shrepoint sites. It seems that if the user is using bluebeam instead of Adobe the files keep duplicating over and over until the user stops sync. The duplicate files have no data in them and can not be opened. I have contacted blue beam but have not been contacted back. I am desparate for a fix. 



I'm not familiar with Bluebeam; is that some kind of productivity software in the same vein as Adobe and Autodesk design/content creation tools? Can you also click on the OneDrive Sync Client icon in your toolbar and open the activity center. That should show you what the sync client is doing which might give us some insight into why the files are duplicating. Thanks!


Stephen Rice

OneDrive Program Manager II

Yes BlueBeam is a PDF tool that allows take-offs and markups. It is heavily used in the construction/engineering industry. When the duplicate files occur the system is detecting conflicts and appending the computer name to the files over and over again until either the user pauses sync or the file path gets too long and it gives up. I also have this issue with users who have Office 2013 installed. Excel files duplicate over and over. @Stephen Rice



Very odd. Let me forward this to one of our sync experts and see if we can figure out what's going on. Thanks!


Stephen Rice

OneDrive Program Manager II

Thanks Stephen.


Laura, sounds like the sync client is forking on the file and making a duplicate copy in order to prevent data-loss. You are saying that this is occuring when syncing an SPO teamsite. Is this always occuring? How many users have the same file open at once? Are individual files being appended with multiple different machine names? How many copies are being created per file/instance?



Great stuff!


The only thing I find users get confused with is related to Sync-ing and Excel. They create and Excel (In OneDrive or SharePoint) which has been sync locally. They start adding links between spreadsheets to reference cells and do vlookups as they have always done in previous versions. It added the link at a local reference, ie. c:\..\SharePoint\TeamSite\filename.xlsx, they then say to people start using the spreadsheet thinking that it is referencing https://xxx.sharepoint.com/sites/TeamSite/Shared%20Documents/filename.xlsx and of course it doesn't work.


Perhaps this is an excel thing, but it would be good if this linking/sync worked out the Unique ID of the file and added that link instead. With a criteria that said look for the unique ID locally first and if it can't find it go to the web version. Does this make sense?



Are that changes only for Onedrive for Business or for Onedrive Personal to?

A) I was under the impression that OneDrive already sync'ed only the parts of a file that had changed, because... efficiency. Does OneDrive (without the Office 2016 integration) actually copy entire files for every little update or change to a file? How often would it be doing this? In the example you describe, with the large video in a PowerPoint file, would OneDrive really upload the entire file every five minutes or so, the whole time you were editing that file if one had this option turned off or if one were using an older version of PowerPoint?


B) Does the Office 2016 program need to be open, with that file open, in order to make these piecemeal synchronizations? Or does enabling this option allow these kinds of piecemeal synchronizations any time after said file has been initially opened by a Office 2016 program?


C) In order to initiate this feature, do I need to open said file from the OneDrive web interface, or do I  open it from the OneDrive folder on my hard drive? Or, Is there some way I can indicate, as I am opening or saving a file, regardless of where it is located, that said file should be added to the list of files that are synchronized via OneDrive? None of the documentation is clear on this point. It just says, "Use Office 2016 to sync Office files that I open," but does not say from where. I know, one could assume they mean "from OneDrive" but one never knows. Plus, this leaves seems to leave the user guessing as to which files will be opened in this manner and which won't. 


Yes, I know I'm being a little pedantic here. But that is what good technical writing is all about. 





If separate users are working on the same file; both Offline; how is the file synced when they return online; at different times.



In the OneDrive settings, you can pick a default on how this is managed.




Hello Stephen

There is something which is not clear for me.

Is this new tool working with sharepoint libraries hosted on a Sharepoint OnPremise ?

We are using OneDrive for Business (groove) with this, for several years, and we have lot's of problems (conflicts not explainable, librairies that become entirely "red", etc), and often the only solution to make OneDrive working again on a client pc is to clean everything (stop synchronizing each librairies, empty office cache, and recynchronizing all librairies) :o(

I would really appreciate if a new tool without those issues could be used to synchronize our sharepoint onpremise librairies...

Thank you for your feedback



What is the reason why the 'Use Office 2016 to sync Office files that I open' doesn't work?  We experience this, and whenever we try to save an offline file, we need to specify a new file name.  It is not possible to save the existing file.  I have seen that MS has recommended switching this feature off. By doing so, we are able to synchronise.  But we lose the confilict resolution feature and instead a new file is created in SharePoint.  Have you been able to find out why this is a problem?





A coworker and I are having trouble getting co-authoring to work for an Excel workbook saved in a SharePoint Online library we each have synced down to our desktops via OneDrive.  When either of us open the workbook, it opens Read-Only by default and forces us to click Edit Workbook to make changes.  Of course, this locks the server copy.  No co-authoring in sight.  What do we need to do in order to get this functionality working using the desktop version of Excel?

Along a similar line... I'm looking for information - or better yet: if there are any detailed lab/test results - regarding the throughput and bandwidth usage of SharePoint Online/OneDrive file sync. What is the effect on WAN performance when a file is updated. For a setup of, say, 100+ workstations at an office location (on a LAN) that are sync'ing to SPO/OneDrive libraries, when SPO/OneDrive is implemented as a replacement for network shared drives: I'm particularly interested in what happens as one file is updated, what does the traffic look like when that file is then sync'd back down to all of the "subscribers". What is the difference (network performance data and user experience) when the file updated is pushed to clients. Then we would like to know what are the possible considerations for maximizing WAN and LAN performance.

Hi Daniel, I do not have a specific answer for you however when you use OneDrive Sync on Demand there wil be no traffic generated unless you have synced the file already. Not everybody will sync the file so the traffic will be user-by-user and only for those who have synced the file.
What are you worry about?

Hi Hans,

I'm aware of Files OnDemand, but that is not what I'm asking about. 


I'm asking specifically about the traffic for files that are stored on users' computers. They need to have some set of files sync'd locally, as they are in a location where internet connectivity is not that great. They will only use Files On Demand for files/folders they don't need to access regularly; but for files they already have sync'd locally, I want to know what is the WAN traffic/load when an updated file is then pushed to clients.


What's to worry about? user experience. There are some 200+ users (~300 devices) in a location with only ok Internet connectivity.

The benchmark user experience we would like to match is that of network shared drive access, which is: no lag time for access/update. Locally sync'd files have better experience, of course, but Files on Demand would have worse experience - due to waiting for file to download over WAN. Bad perception may end up with users rejecting OneDrive sync. We want to implement OneDrive sync, for purposes of business continuity, corporate document management (access by the rest of the organization, etc.).


I'm really curious to see if there are any engineering studies that have been shared and deeper description of the sync client behaviour. I have already been pointed to the Network utilization planning doc

One thing you'll be disappointed to learn @Daniel TSHIN is that unless something has changed since I posted this above several months ago, we've found that even when files are sync'd locally on your PC, Office will still open the file from OneDrive/SharePoint/Internet.  So in the cases where you are in a poorly connected location, you wait a long time for it to open and close/save.

We've never been able to get an answer on why it behaves this way - we had hoped that it would be more like Outlook & cached mode.

Hi @Adrian Hyde, this is not we're experiencing. 

Generally OneDrive NGSC behaves as expected for most of my users.

Today I experienced the opposite of what you're saying. 


One group of users quarterly creates a document (for board of directors) where many people contribute to. Unfortunately this Word documents gets rather large very quickly, > 100MB due to a lot of images over 100 - 200 pages.

Word Online can no longer open this document size, and users rely heavily on Word 2016 with OneDrive NGSC to sync changes to file. With Automatic AutoSave you can quickly expect OneDrive NGSC to fail, as 5-10 users constantly upload and download over 100mb with that document. 


I'm currently in a situation, where the CEO cannot open the Online Version of that file, and Word 2016 constantly opens some cached version that has a few merging errors. I've tried to delete everything offline from that document library, but Word still does not open the proper (most up to date) online version.

@Ivan Unger- my description wasn't clear...

What I mean is if you open the desktop version of Word (for example), and then open a file on your OneDrive - instead of using the version that is already cached on your PC - it will connect to the internet and download the file from OneDrive.

We can see that behavior in Fiddler traces.

We have many users in poorly connected locations, and would prefer to let the sync tool handle the upload/download behind the scenes as much as possible and let the users have the performance experience of working with the locally stored file.

Oh, yes you mean if you select Open from OneDrive/SharePoint, then yes it will open the web version. You'd actually have select the file from the Explorer Window to get the cached version. Now it Office would understand that there is a cached version of this, loading times would definitely improve.

Sorry for reopening an old discussion but I think this is something that we are experiencing also.

From the original post, I expected documents to be opened from the local synced copy but it appears that it opens them from the web which of course takes a lot longer on slower connections.


We can go to file explorer and then open from there (which is quick) and the "recent documents" in Word then show as c:-users-user-OneDrive. Again, opening that recent document is quick.


However, if we go to "recent documents" in Word and open from the connected OneDrive service, it seems much slower which I presume is because it takes it from the online storage rather than the synced local copy.


My expectation was that it would know that a copy was synced and so it would always take it from the local copy - is this not true?

Hello @Richard Rodgers -


Yes -we'd proven a while ago that this original article from @Stephen Rose was not correct...especially this part:


Office files always open from the locally synced file first


We've opened several premier cases who also confirmed the default behavior is that the client will always check the online file first...which really sucks when the network connection is horrible.

But at least there is some potential good news, if you have seen MC172851 - there is an upcoming change for PPT and Word.

We are looking forward to this working on all the Office apps.


New feature: Changes to PowerPoint and Word to open files fasterWe’re excited to release a new change to make documents saved to OneDrive and SharePoint open faster. We’ll be rolling this change out soon. Rather than always checking for updates for cloud files prior to opening, Word and PowerPoint will open any existing version on the user’s device and then sync updates immediately afterwards. This is already the behavior today for files saved to local OneDrive and SharePoint sync folders. This change introduces this behavior for files that are stored on... More ...
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