Number of Cores Incorrectly Detected - Server 2003/XP

Veeam Backup & Replication
6.x, 7
Last Modified:


When adding a Server 2003 or Windows XP machine to Veeam, the true number of cores is not detected properly. Instead Veeam Backup & Replication only detects the number of Sockets.

A virtual machine with Server 2003, having a configuration of 2 Sockets and 4 Cores, is added to Veeam Backup & Replication. On the summary page the following is shown.

User-added image

Additionally the following can be found in the VeeamShell.log
Info     [This server] Determining cpu info.
Info     [This server] PhyCpu: 1, PhyCore: 2, LogCpu: 8.


The cause is the same for both Windows XP and Server 2003. Below is the text from the Microsoft KB article on this topic for Server 2003.

"This issue occurs because Windows Server 2003 does not have the functionality to detect hyperthreading processors and multicore processors. 

Note This functionality was introduced in Windows Vista by using the Win32_ComputerSystem class and the Win32_Processorclass in Windows Management Instrumentation (WMI)."


This issue can be tested by running the following command in PowerShell:

Get-WmiObject -class win32_processor -Property  numberofcores

If this command fails, then you will need to apply the hotfix below, and reboot:

Server 2003 -
Windows XP -

After reboot open the properties for the Windows machine again, and next through the pages to cause Veeam to re-query the number of cores.

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