Note To determine which OneDrive sync client you're using, see the following Microsoft website:
When an external user tries to sync a document library by using the OneDrive for Business sync app for a SharePoint Online site collection or subsite, the user is repeatedly prompted for credentials and receives the following message:
- Browse to the SharePoint admin center.
- On the site collections page, select the check box next to the root site collection. For example, select the check box next to https://contoso.sharepoint.com.
- On the ribbon, click Sharing.
- Select Allow external users who accept sharing invitations and sign in as authenticated users, and then click Save.
- Be aware that by enabling sharing at the root site collection, users can share resources on the site with external users. For more information about external sharing, go to the following Microsoft website:
- Replace the contoso placeholder with the domain that you use for your organization.
Article ID: 3060344 - Last Review: Dec 21, 2016 - Revision: 1