Shared calendars now sync to mobile phones


We are rolling out a feature update that enables shared calendars to sync to mobile phones. This update will make it possible to sync all your Office365 shared calendars to your mobile phone for any permission level (view, edit, or delegate permissions). In addition, you can now share a calendar or accept shared calendar invitations from Outlook on iOS and Android.


Existing shared calendars will not be upgraded as part of this change, and they will continue to sync only to Outlook on the web, Windows, and Mac. Only shared calendars that are accepted after these changes are released will sync to mobile phones.


The shared calendar will only sync to mobile phones if:

  • The calendar is shared between users who are both hosted in Exchange Online
  • The calendar is accepted from a sharing invitation using Outlook on the web, iOS, or Android


We'll be gradually rolling this update starting on 9/18 and rollout will be completed by 9/22.


You can find more details about shared calendar improvements at the article located here.

117 Replies

Thanks Mike for the workaround! Moved all my email to the Gmail app instead of the standard Samsung email app, and now for some reason my standard Samsung calendar app is syncing my Outlook calendars correctly. Weird! Thanks for the suggestion!

Is there a way to remove the shared calendar from my phone, but not Outlook 365? I do not and do not plan to use Outlook 365 on my phone or any other mobile device.


I have tested this on both iPhone and Android devices.


To access office 365 shared resource mailboxes on mobile devices (eg. Mailbox, calendars, etc) 

  1. must be set in office 365 admin -> Shared Mailbox
  2. user must be permitted access
  3. This is not for user account mailbox that is shared

complete the following:


Step #1 Uninstall OWA for iPhone/Android app - IMPORTANT

Step #2 Log into OWA using browser on PC

Step #3 Select Calendar icon

Step #4 Select "Add Calendar" icon on menu, "From Directory" 

Step #5 Search for mailbox shared with user

Step #6 after successful addition, enable shared calendar by selecting it.

Step #7 Install OWA for iPhone/Android

Step #8 configure account in OWA

Step #9 calendar should now be accessible in app, just like OWA on PC.

I thought it was declared that OWA was "dead", non-supported, and that the "new" app was to be used.  Need some chime back from the mother ship to clear up this mess.



It's been a while since I  have been able to work on this project, so apologies for not getting back to you sooner.


We (almost) successfully transitioned our EWS application to Microsoft Graph.  Some of the syncing issues still remain.  These mostly involve updating a large number (>100) of events on a calendar which is syncing to another calendar.  If we delete all the events on a calendar and then add new ones, and run this cycle every 1 to 2 minutes we ultimately see events get duplicated on the "shared" calendar.  This probably comes from the delete process not completing before the add process starts.  On our side we wait for the delete process to complete before starting the add process but it seems to take a long time and it looks like something is getting confused on the Exchange side.  This happened frequently with EWS but still exists to some extent with Graph.


As it is important for our customers to get the integration going we looked at only updating changes in the schedules.  This has worked much more reliably as the changes do not generate the volume of data that the full schedules did.  Briefly we are reading the current schedule from our application and comparing it to the events loaded in exchange by querying them through Graph.  At this point we delete/add only schedules that have changed.


I do think that someone should look at the inability of the system to handle a higher load as I'm sure there will be plenty of developers who try the same thing I did.  Let me know if I can provide any details to facilitate further progress.


As a last (and somewhat related) point, the inability for OWA to correctly handle "all day" events properly has been on going for a while.  Briefly an "all day" event on a calendar posted in one time zone would show incorrectly on a calendar that was set in another time zone.  What would usually happen is that the "all day" event in the original time zone would show for 1 day but it would span 2 days in a different time zone.


There has been a forum discussion relating to this and as of the end of Jan 2018 it seems to have been addressed by Microsoft.


See Jennifer Lu's response at the end of this link.

We have noted an addition problem with this that seems to reside as a UI issue when populating all day events using Graph.  Please see my response to Jennifer on that forum.  I'd be interested in helping to get this resolved.


Again, as always, thanks for making yourself available and helping to push the quality of Office 365 forward.












Hello Julia,

I am customer of a hoster in France that provides me with the Exchange service. I still cannot see our shared calendar as from Outlook iOS. It works with web Outlook but not with the Outlook app, even after re-inviting. I guess my hoster needs to apply a kind of fix or patch to the Exchange so the procedure works. Would you be so kind to share with me what I need to ask them to do (what fix/patch) so we can also share our Calendar in the Outlook app on their Exchange ? Many thanks in advance for your help.

Kind regards,


@bill figures: Thanks for reporting that issue. I was able to repro it, and have opened an item in our backlog to investigate. I believe it has something to do with the way that our web client receives new item notifications, which is why it resets after you open item or refresh page.


@Xavier Jehin: Are you re-accepting the new invite from Outlook on the web, iOS, or Android? It will not sync to mobile if you accept from Outlook on Windows or Mac (but we're working on that!). If you are re-accepting from web, iOS, or Android, please send me a private message with your SMTP address so that I can check your configuration.

I'm rather baffled by this entire thread up until this note that led to some additional research.  So let me get this straight MS... you added the ability to see shared resources in the mobile OWA app, then immediately discontinued that app, did not update any of your KB articles, and have not put the ability in the Outlook mobile app?  Because fact is, you can NOT access shared calendars in Outlook mobile on iOS or Android, and your support people in those apps have confirmed this limitation.  It's crippling, because you also don't make shared calendars available via Exchange configuration in the Mac OS or iOS.  So mobile is left in the dark and you're forced in every way to use Outlook on PC and Mac because you're apparently violating your own standards so Exchange developers can't access these resources in their apps?  I'm really baffled by all this, especially given what a huge enterprise product this is....

Hi Julia,


I am having a huge problem as since the 9/2017 update whenever someone shares there calendar with me I cannot turn it off so that it is not on my Mobile phone. I would like to be able to see events when necessary, but not have 10 or more people's schedule on my personal mobile phone at all times. It becomes cluttered and confusing.  Even when I deselect their calendar on the web outlook calendar it remains on my mobile phone.  When I delete the events from my mobile phone I have been told that it deletes the persons calendar event.  I notice that this only occurs for those who are listed under "People's"Calendar and not "Others" Calendar.  I assume they labels changed after 9/2017.  Is there any fix for this because it is causing me great headaches. 

Hi Keisha,

This is the same problem I had.  The only solution was to rely on the Outlook App Calendar for my work meetings/appts and keep my personal calendar separate (i use gmail and the samsung calendar).  When in Outlook App calendar, when you select the menu top leftyou can de-select the shared views calendar.  It is frustrating that I have to view two separate calendar apps but this was the only way I could work it. 

Unless they've changed it again shared calendars won't appear on your mobile device if they've been added using the desktop outlook app instead of outlook online.  They will still be available in outlook online though, the important part is how they're added not how they're accessed.


On apple devices you should be able to turn individual calendars on and off.  On android devices you can also pick individual calendars depending on the specific combination of apps you're using.  I've found that as long as you use the gmail app to setup the sync to your exchange account it will let you control the calendars individually but not if you use your phone manufacturer's email app.


If you don't need the calendars while mobile at all I would remove them from your shared list and re-add them using the outlook desktop app.  If you need the ability to turn them off and on selectively (and you're on android) I would setup your email in the gmail app.  Then you should be able to turn the individual calendars on and off in your calendar app.  You might have to experiment some.


I hope that helps, this feature isn't well documented.

Does this apply to shared resource calendar's as well? My current app that I use, OWA for iOS, says that it will be retired on May 15 so I have switched to Outlook for iOS, but I cannot see a shared resource calendar that am owner of (there are four owners so we can all edit the calendar).


Any advice you have would be welcome. Thank you!



Yes, it applies to shared resource calendars as well. You'll need to login & share the resource calendar directly to you (or the admin can do it via a cmdlet), and then you'll need to accept that sharing invitation from Outlook on the web, iOS, or Android.

We are investigating simpler ways to get this setup that doesn't require re-sharing the calendar -- stay tuned!

When I click on the link in the OP it doesn't resolve for me


I'm looking to fully understand how this is implemented, but I'm not finding more information from Microsoft, even just basic how-tos or KBs on these. I have a feeling I just don't know where to look. 

Hi Trevor, there are some issues with these links in the Safari browser. Here's the destination URL that should provide you the details you're looking for:

I need to turn this off.  We have multiple people with multiple appointments per day.  When I am at my desktop I can check where everyone is and schedule appointments for them,  but when i am out and about I need to know where I have to be.  I don't want 30+ other appointments on my screen.  You need to make this optional or I have to turn off all shared calanders, which then means i can't schedule my people when I am in the office.  This is really frustrating.

Hi Shay,
You can select/unselect the calendars shown in the calendar app if you don't want to see other people's calendars on your mobile phone. Note that not all Android calendar apps allow this, but the Outlook mobile app on Android does.

@Julia Foran wrote:
Yes, it applies to shared resource calendars as well. You'll need to login & share the resource calendar directly to you (or the admin can do it via a cmdlet), and then you'll need to accept that sharing invitation from Outlook on the web, iOS, or Android.

We are investigating simpler ways to get this setup that doesn't require re-sharing the calendar -- stay tuned!

You mention there is a cmdlet to send a sharing invitation. What is that cmdlet?

The cmdlet is the Add/Set-MailboxFolderPermission cmdlet (documented here). When setting permissions on a calendar folder, you can use the -SendNotification $true parameter to send a sharing invitation email, which would be equivalent to logging into the room mailbox & sharing from there.

Why can't we just see the shared mailbox and shared calendar in the Outlook mobile app just like in the Outlook desktop app without the hassle? I seriously don't understand.


This workaround helps me to have a working shared calendar on my Iphone, but on my desktop I now have double calendar notifications because my shared calendar shows up twice.