365 Groups "Full Teamsite" & External Sharing

New Contributor

I tried to share a single library/file from an 365 group's teamsite with an external user not beeing a member of the group. Regretfully, SharePoint does not allow it, telling me its prohibited by policy. 


Of course, external sharing is setup/allowed. As I can not view/change the setting for the hidden SP-site via the admin interface - is this possible/intended at all?



Thanks for your help


18 Replies
External Sharing in Groups relies on Guest access support in Grpoups that has to be configured at the tenant level:



Thanks for your quick reply, but I'm aware of that and it's enabled.


The scenario I tried to describe is different: I tried to share a single library/file from an 365 group's SP teamsite with an external user not beeing a member of the group. I don't want to share the whole site/communication/... with the user, only parts of it.


Any ideas on that?


It'll be interesting to see what shakes out about this use case. I can totally see the use case and how it's relevant and my microsoft programmed brain would say "because it's an office 365 group and meant to use the new azure ad objects it won't be supported because groups is an all or nothing situation"

But I also know that you can use granular permissions in the hidden SharePoint site collection and I know that because it's a SharePoint site collection it should in theory be able to turn on the external sharing and support this use case.

Normal business is the use-case :)

Assume an internal-team that does discussions, uses the notebook, organizes itself in planner but also wants to be able to share some results (documents or apps e.g. issue tracking) with an external audience. Of course, I can create another SP site for it, but why? ... it's all there.

My understanding of "full SP site" is different :)

Hi Markus. I absolutely agree the use case is a normal day to day business one.

You can't teach people "Share with links rather than attachments" and "Office 365 groups are the best way to easy collaboration" and then when using groups take away their easy method of sharing a specific file with an external and I definitely hope this will be resolved by MS.

You cannot able to share files to user who is not the member of the group because ' Allow sharing only with the external users that already exist in your organization's directory' is enabled in SharePoint and there is no way to change this as the site for Office 365 Groups is hidden.

It is only possible to share file to external user who is not the part of Office 365 Groups by adding the user in Azure AD B2B.
Thanks for clarifying that Santhosh. Saves me from digging into the details myself to see if it was possible!



You're right and the error message in SP is more than missleading - wrong! Having that in mind, it's even more than weired:


The 365 group dialog let you add external users that get invited to your AD.

You can also share content on the SP site with external users that exist in your AD. But you cannot use automated invitation+external user provisioning functionality through SharePoint? 


In my opinion, it's simply wrong that the SP site is configured to 'only with existing users' if the 365 tenant allowes external invitation. 


For my business case, there is a workarround that solves it, but one should be allowed to control that behavior at will.


Thanks for helping me understand "error messages" :)



best response confirmed by Markus Kling (New Contributor)

You can change the default using PowerShell.



"By default, all SharePoint site collections that are part of an Office 365 Group have the sharing setting set to Allow sharing only with the external users that already exist in your organization’s directory. To change this setting, you can use the Set-SPOSite Windows PowerShell cmdlet."


When the oldest groups will be converted in full team website ?

AFAIK, for First Release tenants, modern SharePoint Online team sites have already come to all existing Office 365 Groups ...

Thanks for the feedback everyone.  For group connected sites, the default sharing setting is to enable sharing with existing external guests.  This can be changed as noted earlier in the thread via PowerShell:


Currently, all groups in First Release tenants should have the full SharePoint site unlocked.  Are you not seeing this today?

No ... Still not ... only 2 groups / 30 are updated up to now ... Maybe be later ?

You can only share Office 365 group document library with guests who have been invited to join the group. But individual group files can be still shared with guests users through file sharing from SharePoint Online

Hi Markus,


try this one: 

Set-SPOSite -Identity -SharingCapability ExternalUserAndGuestSharing

This worked for me.





Was this topic you had ever resolved?  I am struggling with the same question from my users.  Any insight or solutions to this problem would be helpful.


Thank you,