ESXi/ESX host fails with a purple diagnostic screen that displays: TimerAlloc
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ESXi/ESX host fails with a purple diagnostic screen that displays: TimerAlloc


Article ID: 310441


Updated On:


VMware vSphere ESXi


This article describes a specific issue. If you experience all of the above symptoms, consult the sections below. If you experience some but not all of these symptoms, your issue is not related to this article. Search for your symptoms in the Knowledge Base or file a Support Request. For more information, see Filing a Support Request in Customer Connect (2006985).

  • An ESXi/ESX host stops responding and displays a purple diagnostic screen indicating that a Page Fault (#PF) or General Protection Fault (#GP) exception has occurred.
  • The purple diagnostic screen contains information similar to:

    TimerAlloc@vmkernel#nover+0xnn stack: 0xnn
    Timer_AddTCWithLockDomain@vmkernel#nover+0xnn stack: 0xnn
    Timer_AddTC@vmkernel#nover+0xnn stack: 0xnn
    FastSlab_AllocWithTimeout@vmkernel#nover+0xnn stack: 0xnn

  • The ESXi/ESX host is using Intel Xeon CPUs that support Intel FlexPriority.


VMware ESXi 4.1.x Installable
VMware vSphere ESXi 5.0
VMware vSphere ESXi 5.1
VMware ESX 4.1.x
VMware ESXi 4.1.x Embedded


This is a known issue affecting ESXi/ESX 4.1 and ESXi 5.0/5.1.

To resolve this issue, upgrade the system BIOS or firmware. For more information, click on the link corresponding to your system to review the hardware vendor's advisory or BIOS release notes:
Note: The preceding links were correct as of May 27, 2014. If you find a link is broken, provide feedback and a VMware employee will update the link.


To work around this issue on your version of ESXi/ESX when you cannot upgrade the BIOS on the server, install the applicable patch to disable Intel FlexPriority.

To disable Intel FlexPriority, install one of these patches:

Additional Information

For more information, see Interpreting an ESX/ESXi host purple diagnostic screen (1004250).

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