Summary
Vmss2core is a tool to convert VMware checkpoint state files into formats that third party debugger tools understand. It can handle both suspend (.vmss) and snapshot (.vmsn) checkpoint state files (hereafter referred to as a ‘vmss file’) as well as both monolithic and non-monolithic (separate .vmem file) encapsulation of checkpoint state data.
Features
The vmss2core tool can produce core dump files for the Windows debugger (WinDbg), Red Hat crash compatible core files, a physical memory view suitable for the Gnu debugger gdb, Solaris MDB (XXX), and Mac OS X formats. Debugging Virtual Machines with the Checkpoint to Core Tool provides the usage information for the vmss2core tool.
System Requirements
VMware Fusion Support Center FAQs and VMware Workstation 9 System Requirements provide the system requirements.
In addition, Windows hosts also need to have Visual Studio 2008 Service Pack 1 runtime installed. Please see http://www.microsoft.com/en-us/download/details.aspx?id=26368 for instructions on getting the runtime.
Workstation Host System Requirements:
https://www.vmware.com/pdf/ws80-getting-started.pdf
Fusion Host System Requirements:
https://www.vmware.com/pdf/fusion_getting_started_40.pdf
Instructions
For instructions on how to use vmss2core see Debugging Virtual Machines with the
Checkpoint to Core Tool
Video
Change Log
Engineers
![]() | Doug CovelliWorks in the Monitor group. |

Hi,
The Windows download here appears to behave differently from the one installed on my work laptop with Workstation 9. I ran the command specified in the documentation (vmss2core -W .vmss .vmem); the old version ran perfectly on all Windows VMs, but the fresh download failed with the message
“cannot locate cpu.CR[0] for VCPU 0.
Cannot create memory.dmp
Finished writing core. ”
What changed and how should I alter my behavior to make it work?
Great idea.. it doesn’t work with ESXi 5.1 format. Can we get it updated?
Ian it works fine with esxi 5.1 format. I just did that, by running vmss2core against snapshot file.