The remote server returned an error: (401) Unauthorized for Microsoft Loop SharePoint sites
Challenge
The Backup of SharePoint sites displays the following error:
Failed to initialize site processing: /contentstorage/CSP_<guid>, error: The remote server returned an error: (401) Unauthorized.
Cause
Microsoft recently launched a new feature called "Microsoft Loop." This application creates a SharePoint site to store shared content that can be accessed by users who have been invited to use Loop. The URL of these sites contains the "contentstorage" identifier.
For more information about Loop, you can visit these resources:
- https://loop.microsoft.com/learn
- https://techcommunity.microsoft.com/t5/microsoft-sharepoint-blog/the-sharepoint-storage-platform-supports-the-loop-app-components/ba-p/3772852?WT.mc_id=M365-MVP-9501
These sites have unique permissions assigned to them, and currently, Veeam Backup for Microsoft 365 does not support them. However, once Microsoft Loop becomes generally available, support for this feature will be developed.
Solution
This hotfix does not add support for sites created by Loop; it allows Veeam Backup for Microsoft 365 jobs to skip such sites silently.
- Ensure you are running Veeam Backup for Microsoft 365 7 P20230302 (7.0.0.2914).
- Ensure that there are no Backup jobs or Restore sessions running.
- On the Veeam Backup for Microsoft 365 server, stop the following services:
- Veeam Backup for Microsoft 365 Service
- Veeam Backup Proxy for Microsoft 365 Service
- Veeam Backup for Microsoft 365 REST API Service
- Download the hotfix via the button below.
- Extract the fix to: C:\Temp\KB4440\
- After extraction, unblock the files using the following PowerShell cmdlet:
- Back upEither zip the old dll or rename it to add .kb4440original after the .dll extension. and replace the the DLL file in each of the following locations:
- Veeam.Archiver.Source.dll
- C:\Program Files\Veeam\Backup365\
- C:\Program Files\Veeam\Backup365\Packages\Proxy\
- Veeam.Archiver.Source.dll
- Start the services that were stopped in Step 3.
- Upgrade the Backup Proxy Servers.
Download Information
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