The Goal

Share one specific folder in a SharePoint site with an external user (outside of tenant organization) and include Edit permissions without the user needing a Microsoft account.

My Environment

  • SharePoint Online
  • Admin Center > Policies > External Sharing > Most Permissive/Anyone (See a screenshot here)
  • Admin Center > Site > External Sharing > Anyone (See a screenshot here)
  • I do have custom code running: tenant wide extensions and web parts.

Expected and normal behavior

Microsoft confirmed (via my personal ticket) that it is possible to share just one folder to an external user. I also tested it on another tenant and the external sharing was successful. Therefore, I know it's something to do with my specific tenant.

The Issue

When I share the folder via "Copy Link" or "Share", after the external user enters the verification code, they can open the folder and it appears just briefly (1/2 seconds), but then the page gets redirected to my organizations' login screen.

When I share the folder via "Manage Access" > "Advanced" > "Grant Permissions": enter image description here

It won't even let me share it. I get an error within the browser: enter image description here

Sharing failed: Operation is not valid due to the current state of the object.

The issue occurs on all classic and modern Team and Communication sites.

However, I am able to get it working on one specific classic Team site.

1 Answer 1


I had a custom-built tenant-wide SharePoint extension installed and active which was doing a "behind-the-scenes" user authentication (I think through aadHttpClientFactory) that caused any external user to hit a sign-in wall.

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