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Release Information for Veeam Backup for Microsoft 365 8.1 and Cumulative Patches

KB ID: 4711
Product: Veeam Backup for Microsoft 365 | 8.1
Published: 2025-01-23
Last Modified: 2025-02-12
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Requirements

This release can be used to:

  • update manually from a previous Veeam Backup for Microsoft 365 8.1 release to the latest Cumulative Patch.
  • upgrade an existing v7 or v8 deployment of Veeam Backup for Microsoft 365 to v8.1.
  • install a new deployment of Veeam Backup for Microsoft 365 v8.1.

After installing this release, the Veeam Backup for Microsoft 365 build number will be 8.1.0.331.

Release Information

8.1.0.331

2025-02-11
Resolved Issues
  • In highly loaded environments, processing operations executed on a proxy pool may take longer than expected after one of the proxies in the pool has been restarted, removed, or gone offline.

8.1.0.305

2025-01-23
Enhancements
  • Support for Ubuntu 24.04 and RedHat 9.4 as backup proxy operating systems.
  • Multiple stability, performance, and scalability improvements delivered to ensure product reliability.
Resolved Issues

General

  • Repository indexing may fail with the error:
    Retry transient error after 00:00:00: Npgsql.NpgsqlException (0x80004005): Exception while reading from stream.
    
  • Protection of a host running Veeam Backup for Microsoft 365 using other Veeam solutions may fail with the error:
    VSSControl: Failed to prepare guest for freeze, wait timeout {value} sec.
    
  • Under certain conditions, retention cleanup may fail to start, displaying the error:
    Cannot start the retention session because this repository is in use by other sessions.
    
  • On immutable object storage repositories associated with a proxy  pool, the extension of the immutability period may fail with the error:
    Item previews are missing (ID: {ID} ({value} bytes)).
    

Upgrade 

  • Upgrading a Linux proxy in a proxy pool may fail with the error:
    The command timed out: sudo systemctl stop Veeam.Archiver.Proxy. Current output: {proxy name} was not upgraded.
    
  • Under certain conditions, indexing and upgrading an object storage repository may get stuck.
  • Upgrading an object storage repository may get stuck.
  • Under certain conditions, upgrading an object storage repository may fail with the error:
    Cannot find a web backup for the internal web ID: {ID}.
    

Backup and Backup Copy

  • A backup or backup copy job with SharePoint, OneDrive, or Teams data may fail with the error:
    Cannot find object {path}.
    
    For more details, see KB4678.
  • Under certain conditions, an Exchange backup job processed in a proxy pool may remain stuck in a running state.
  • Under certain conditions, a backup job processed in a proxy pool may become stuck in a running or failed state, and attempts to stop or restart the job fail with errors.
  • An Exchange backup job may fail with the error:
    Processing mailbox {user@domain.com} failed with error: Unable to access object storage (reason: Cannot access a disposed object. Object name: 'Veeam.Core.Memory.Reference`2.
    
  • A OneDrive backup job may mistakenly attempt to download items blocked by a virus scanner, resulting in a failure with the warning: Failed to backup item:
    {path}, Failed to download block in time: {time}.
    
  • The size of backup data transferred by a backup copy job can significantly exceed the size of the source data.
  • An Exchange backup to an object storage repository may fail with the error:
    Npgsql.PostgresException (0x80004005): 23505: duplicate key value violates unique constraint “pk_exchange_items_previews_uploads”.
    
  • Under certain conditions, a backup copy job transferring SharePoint and Teams data may get stuck in the running state.
  • Under certain rare conditions, a backup copy job transferring Exchange data to an archive-tier object storage repository fails with the error:
    The response status code does not indicate success: 409 (this operation is not permitted on an archived blob).
    

Restore

  • In Veeam Explorer for Microsoft SharePoint, browsing a SharePoint, Teams (files), or OneDrive backup from an object storage repository may fail with the error:
    Cannot find object {path} or Task failed with exception (task ID: {ID}).
    
    For more details, see KB4678.
  • Restoring of Exchange data may fail with the error:
    Failed to get task result because the task does not exist (ID: {ID}).
    
  • Under certain rare conditions, when exploring SharePoint backups stored in a Jet-based repository, some items may not be displayed. For more details, see KB4704.
  • When initiated via REST APIs, exploring a SharePoint backup containing a Discussion Board may fail with the error:
    Object reference not set to an instance of an object.
    
  • In Veeam Explorer for Microsoft Exchange, when an email item is exported to a .MSG file, diacritics are replaced with fallback characters.
  • Veeam Explorer for Microsoft SharePoint may not display any content if the backup was retrieved from an archive-tier object storage.

REST APIs

  • Execution of the following endpoint with the useAuthentication parameter set to false may fail with the error below:
    (POST) /v8/RestoreSessions/{restoreSessionId}/organization/mailboxes/{mailboxId}/items/sendToDifferentAddress
    Object reference not set to an instance of an object.
    

Manual Updating

To manually update an existing Veeam Backup for Microsoft 365 version 8.1 (8.1.x) deployment to the latest Cumulative Patch listed on this page, follow the same steps as upgrading Veeam Backup for Microsoft 365.

  1. Download the latest ISO.
  2. Ensure that there are no active Backup or Restore sessions running.
  3. Close all Veeam Backup for Microsoft 365 and PowerShell consoles.
  4. Mount the ISO on the Veeam Backup for Microsoft 365 server.
  5. Run Veeam.Setup from the ISO.
  6. Click Update and follow the prompts to update the software.
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