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Virtual machine fails with the error: Unrecoverable Memory Allocation Failure (1023749)

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  • A virtual machine fails with the error:

    Unrecoverable Memory Allocation Failure

  • A virtual machine VMX core dump is generated with a name similar to:


  • When you try to connect to the virtual machine through a vCenter Server console, a black screen appears with the message:

    Unable to connect to MKS: vmx connection handshake failed for vmfs {VM Path}

  • The virtual machine's vmware.log file contains entries similar to:

    vcpu-0| Attempt to allocate 0 bytes of memory failed
    vcpu-0| SCSI-DEV ide0:0: HBAHosted_PreIo failed for command TEST UNIT READY

    vmx| Msg_Post: Error
    vmx| [msg.log.error.unrecoverable] VMware ESX unrecoverable error: (vmx)
    vmx| Unrecoverable memory allocation failure at bora/lib/disklib/changeTrackerESX.c:433
    vmx| [msg.panic.haveCore] A core file is available in "/vmfs/volumes/<VMFS UUID>/VM_Name/vmware-vmx-zdump.000".

    vcpu-0| SVGAGMR: Mapping failed at descriptor #0 in GMR #2: Can't map 70893593 pages at PPN 0x0539c219.
    vcpu-0| SVGAGMR: Error reading descriptor table at PPN 0x0002c872

    vcpu-0| VMKernel_SetupPhysMemMap(pagein, 196610 pages) failed: Not found
    vcpu-0| Unexpected return status from VMKernel_SetupPhysMemMap(pagein, 196610 pages): Not foundBacktrace:
    vcpu-0| Backtrace[0] 0x27c81bb8 eip 0xd8218ed

    vcpu-0| Unrecoverable memory allocation failure at bora/lib/user/msg.c:220

    vcpu-0| Attempt to allocate 0 bytes of memory failed
    vcpu-0| SCSI-DEV ide1:0: HBAHosted_PreIo failed for command LOCK/UNLOCK DOOR
    vcpu-0| Unrecoverable memory allocation failure at bora/lib/user/dictionary.c:1251


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, review Determining why a virtual machine was powered off or restarted (1019064) and Interpreting virtual machine monitor and executable failures (1019471) for similar issues, or Open a Support Request.


This issue occurs due to non-availability of memory for the VMX process, resulting in a virtual machine failure. The vmx process was updated to resolve this issue in ESXi/ESX 4.0 Update 2.

To resolve this issue, upgrade your product installation to ESXi/ESX 4.0 Update 2 or later. For more information about the available updates, download links, and release bulletins, see the Download Patches page.

Additional Information

For information on the location of log files in ESX, see Location of ESX 3.0-4.1 log files (1021800) and Location of log files for VMware products (1021806).



See Also

Update History

10/09/2011 - Added content from KB 1026892.

Request a Product Feature

To request a new product feature or to provide feedback on a VMware product, please visit the Request a Product Feature page.


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