Only 1 CPU appearing in task manager on Windows 2003 Server even though 2 are added in VCenter.

If you've tried rebooting the server and the second CPU is still not showing up in task manager, follow these steps:

  1. RDP to server
  2. Open Device Manager
  3. Expand > Computer
  4. In the sub list you will see something other than ACPI Multiprocessor PC e.g:
    Standard PC
    ACPI Uniprocessor PC
  5. Right click the item under Computer
  6. Select > Properties > Driver > Update Driver
  7. Choose:
    No, not this time > Next
    Install from a list of specific location > Next
    Don't search. I will choose the driver to install > Next
  8. Untick "Show compatible hardware"
  9. Select:
    ACPI Multiprocessor PC
  10. Click: Next > Finish
  11. Reboot the machine. The second CPU will now work

If ACPI Multiprocessor PC is not available in the list, follow these steps:

  1. In the RDP session, download the following file to the machine with the issue:
  2. Extract: devcon.exe
  3. Copy to: C:\Windows\system32
  4. Run the following commands:

devcon.exe sethwid @ROOT\PCI_HAL\0000 := +%HAL%
devcon.exe sethwid @ROOT\ACPI_HAL\0000 := +%HAL%
devcon.exe update %windir%\inf\hal.inf %HAL%
devcon.exe ReScan

Ensure that the "devcon.exe update %windir%\inf\hal.inf %HAL%" command does not report a failure. 
If it does fail, it may be necessary to temporarily install another HAL either from Device Manager 
or by changing the SET HAL=ACPIAPIC_MP line and re-running the script. 

You will now be able to select: ACPI Multiprocessor PC as discussed above.
Reboot the machine and the second CPU will now work.

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devcon - app for multiCPU issu... 79.0 kB 1 24-May-2017 15:30 Hyve Support
« This page (revision-2) was last changed on 24-May-2017 15:30 by Hyve Support
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