Unable to determine guest operating system

I am in the process of converting from VMWare Server 1.02 to VI3, and have been getting the unhelpful "unable to determine guest operating system" error messages when trying to convert.

I am running VMWare Converter on a Windows XP SP2 laptop, with a mapped drive to a NAS device with all the VM images on it. All the VMs are shut down then copied to the NAS device. Here is what I have found so far that causes the error message:

1. Incorrect permissions (need read/write, not just read)

2. Disks that are set up as single growable virtual disk. I don't do preallocated, but single growable gives me the problem, I had to convert them to growable split into 2Gb files.

3. Having multiple virtual disks specified in the VMX but only having one or some of them available where they were specified. Explanation: I had a VM with 3 disks, one single growable and two 2GB growable. I copied the single growable virtual disk to the Converter machine, converted to 2GB growable, and tried to run Converter without copying over the other two disks. After putting all three 2GB growable disks in the same directory, it worked fine.

It appears that the error message "unable to determine guest operating system" happens when it has disks that it is unable to work with, not just when there is an issue with the OS selection. This looks like a bug in the UI, where it doesn't really pass along correct information on the actual error. This needs to be corrected, and the documentation should mention the 2GB growable requirement.

I am continuing to test and convert, so I may have more to add (or I may be wrong in some cases).


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2 Replies

I am actually having same error message "unable to determine guest operating system", but I observed that this does not apply to every VMs. Some seem to work without any problem while other generate this error mesage.


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I have been doing some testing and also come across this issue, I have compared across a number of VMs and not been able to tie it down to anything specific around the following so far:

LSI v BusLogic Disks

Windows 2000 v Windows 2003

ESX 2 VMs v ESX 3 VMs

Microsoft VMs v VMware VMs

Number of disk files within the VM

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