When importing an OS layer, you get this error:

Failed to attach the disk /mnt/repository/Unidesk/OsImport Disks/Windows 10.vhd. Failed to probe partitions from virtual disk

This is most often seen when importing a XenServer Windows 10 Gold VM that was exported as an OVF.  However, it could happen in any Gold Image.

To fix this, go back to your Gold VM and extend the virtual disk by something small, like 1GB. Don't go into Windows and extend the partition, just leave the extra space at the end empty. That way the partition will be completely inside the virtual disk even if 1MB is shaved off the end again.

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Problem Cause

There may be other reasons you could get this error, like the customer is using EFI or GPT partition tables. Unidesk requires MBR partition tables currently.

But if you get this error:

Failed to attach the disk /mnt/repository/Unidesk/OsImport Disks/Windows 10.vhd. Failed to probe partitions from virtual disk

Collect logs from Citrix Enterprise Layer Manager (ELM) as described in  https://support.citrix.com/article/CTX223723. When you export logs, the Citrix software creates a gzipped tar file (.tgz) containing the log files. On extracting the .tgz log file you will find camlogfile.



Open the camlogifle in notepad and see if you have a block like this:

2016-07-15 12:53:39,717 ERROR DefaultPool3 AttachDiskJobStep: Disk attach failed, detaching /dev/nbd255 Message: MessageId=FailedProbeVirtualDiskPartitions, DefaultTitle=, CategoryData={[ExternalToolFailure { Call = "/bin/nice", Args = "-n-10 /sbin/partprobe /dev/nbd255", Output = "", Error = "Warning: Error fsyncing/closing /dev/nbd255: Input/output error
Warning: Error fsyncing/closing /dev/nbd255: Input/output error
Error: Can't have a partition outside the disk!
Warning: Error fsyncing/closing /dev/nbd255: Input/output error", ErrorCode = 1 }]}

The important bit is that "Can't have a partition outside the disk!" line.

For reasons we don't yet understand, sometimes the ELM's way of mounting up a disk comes up about 1MB short. If you mount the same disk to a VM through a hypervisor, the size is correct, but in the ELM, the size is reported just a hair too small. The partition then ends just slightly after the end of the disk, which is illegal.

Failed to attach the disk /mnt/repository/Unidesk/OsImport Disks/Windows 10.vhd. Failed to probe partitions from virtual disk