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Veeam Backup for Microsoft Office 365 4c cumulative patch KB3222


Veeam Backup for Microsoft Office 365 4c cumulative patch KB3222.


Please confirm you are running Veeam Backup for Microsoft Office 365 build prior to installing this cumulative patch KB3222. You can check this under Help > About in Veeam Backup for Microsoft Office 365 console. After upgrading, your build version will change to

As a result of on-going R&D effort and in response to customer feedback, cumulative patch KB3222 provides a set of enhancements and bug fixes, the most significant of which are listed below:


  • Optimized reading from object storage repository to reduce the cost of querying the first 100 items in a folder when exploring backups with Veeam Explorers.
  • Parallel processing of requests for obtaining used space in backup repositories initiated via PowerShell or REST API on multiple proxies.
  • Reduced backup times to object storage repositories targets when processing SharePoint and OneDrive for Business items with thousands of versions.

Resolved Issues

  • After updating to Veeam Backup for Microsoft Office 365 4c (build backups start to fail with the “Proxy offline time exceeded” error. For more details, see KB3216.
  • Under certain conditions, the backup proxy server sends ‘Success’ notifications about backup job completion results for backup jobs failed with the “Proxy offline time exceeded” error.
  • Unable to update certificate information for S3 Compatible object storage after the trusted certificate has been changed and a backup repository extended to such object storage goes to the ‘Invalid’ state.
  • OneDrive restore in the Modern Authentication mode fails with the “Cannot connect to Office 365” error.
  • Backup job initiated with the /v4/Jobs/{backup_job_id}/action REST API request performs full backup sync instead of incremental sync.
  • In the UI, changes to the schedule of applying retention policy settings for existing backup repositories are not saved.
  • SharePoint backup fails with the “The Attachments column does not exist. It may have been removed by another user” error.
  • Under certain conditions, in the Modern Authentication mode with legacy protocols enabled, Public Folder mailbox backup fails with the “Too many concurrent connections opened. Cannot open mailbox” error.


To install the cumulative patch KB3222:
  • Download
  • Execute VeeamBackupOffice365_4.0.1.545_KB3222.msp as administrator on the Veeam Backup for Microsoft Office 365 server.

If there are any remote proxies in your environment, please update those as described here.

More information


MD5: a04037ee1830e578e3329c8932225eef
SHA-1: 9c075746fbb324d6a3695b5641e4a535b29ace5a
Veeam Backup for Microsoft Office 365
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