Proxmox VE Compatibility with Veeam Backup Server OS Server 2012 and 2012 R2

After adding Proxmox VE (PVE) hosts to Veeam Backup & Replication, the workers are deployed, but the testing phase fails with the error:

If the server where Veeam Backup & Replication is installed is running Server 2012:

System.ComponentModel.Win32Exception (0x80090308): The token supplied to the function is invalid

If the server where Veeam Backup & Replication is installed is running Server 2012 R2:

Failed to connect to the worker core service: Failed to connect to the backup appliance

Option 1: Upgrade the Windows OS

Upgrade the machine that Veeam Backup & Replication is installed on to Windows Server 2016 or newer.

Recomended, considering both Server 2012 and Server 2012 R2 reached End of Life in October of 2023.

Solution 2: Apply Security Update 3174644

If an upgrade is not feasible, install Security Advisory# 3174644 to the Server 2012/2012 R2 machine where Veeam Backup & Replication is installed.

• https://learn.microsoft.com/en-us/security-updates/SecurityAdvisories/2016/3174644
• https://catalog.update.microsoft.com/Search.aspx?q=KB3174644