Please confirm you are running Veeam Backup for Microsoft Office 365 build 126.96.36.1991 or 188.8.131.523 prior to installing this cumulative patch KB4078. You can check this by clicking Help and Support > About in the main menu of the Veeam Backup for Microsoft Office 365 console. After upgrading, your build version will change to 184.108.40.2060 (version 5a).
As a result of on-going R&D effort and in response to customer feedback, cumulative patch KB4078 provides a set of enhancements and bug fixes, the most significant of which are listed below:
After upgrading to Veeam Backup for Microsoft Office 365 version 220.127.116.111, a local backup repository fails to upgrade with the “Error: JetError -1605, JET_errKeyDuplicate, Illegal duplicate key” error.
Personal sites are not backed up using a backup job that is configured to protect an entire organization.
Updating the installed product license fails with the “Failed to check for license update” error.
Checking for available product updates fails with the “Failed to check for updates” status.
After upgrading to version 5, browsing backups with Veeam Explorer for Microsoft Exchange fails with the "Unable to find mailbox account" error.
If a local repository was configured with the snapshot-based retention, Microsoft Teams data that is within the specified retention period may be unavailable for browsing after retention cleanup is applied.
To install the cumulative patch KB4078:
If there are any remote proxies in your environment, update those as described here.