Share a document library with external users

[Oz Oscroft]

 Hi all.  We have an Office 365 Group set up for a project.  It has 2 document libraries (DocLibA & DocLibB).  I'd like to share library DocLibB with some external users who are advising on the project, but ensure they can't see anything else in the group.

I'd assumed this would be quite simple, but after lots of searching and reading support documents, I've failed.  Any advice would be gratefully received.

Really hoping you can help as this is driving me nuts.  Thanks, Oz

[#2]

Well...this is something you can definitively do since in the end you have SPO behind the scenes....so you could potentially stop permission inheritance in the doc libraries and configure security to meet your needs...but bear also in mind that you could find some unexpected problems when customizing security

[#3]

Thanks Juan Carlos.  I'm not even getting to that stage unfortunately - here's what I'm finding:

1. I'm an owner of the Group and can add guests (external users) to the Group via Outlook.  This gives them access to everything in the Group as expected.
2. If I go to a document library, select a folder or file, click share, select 'Specific people' and type in an external email address (of someone who's not already a member), I get the following error:
   "Your organization's policies on't allow you to share with these users.  Please contact your IT department for help".  Unfortunately I work for a very small company and I AM the IT department!
3. In the Office 365 Admin Center > Settings > Security & Privacy > Sharing:
   1. 'Let users add new guests to the organization' = On.
   2. Under Site Settings, 'Let users share SharePoint Online and OneDrive for Business content with people outside the organization' = On.
   3. Users can share with = 'New and existing external users (sign-in required)'.
4. In the Office 365 Admin Center > Settings > Services & add-ins > Office 365 Groups:
   1.  Let group members outside the organization access group content = On
      [QUESTION: Is it possible to change this setting for one specific group?]
   2. Let group owners add people outside the organization to groups = On

Does this therefore mean that an external guest has to be a member of the Group BEFORE I can share a link to a folder / document with them?  All I really want to do is share the documents within one doc library with specific external users and not anything else.

Really hoping you can help.  Thanks again, Oz

[#4]

Is there any good solution for that?

I am also interesting to know.

Actually I want to share READONLY (aka visitors) a doc library

The very easiest way to secure external sharing is to add the external in the group (I am an owner), but then they (external) have R/W access to the site and to the library

[#5]

You need to enable guest sharing on the site:

The Powershell code (to be run as an admin) is:

• a. Set-ExecutionPolicy Unrestricted
• b. $UserCredential = Get-Credential
• c. Connect-SPOService -URL https://<domain>-admin.sharepoint.com
• Set-SPOSite -Identity https://<domain>.sharepoint.com/sites/<sitename> -SharingCapability ExternalUserAndGuestSharing