Restore Vmware From Delta Vmdk 'link'

This is the safest method. Instead of modifying the original VM, you attach the delta disk to a "Helper VM" to copy the data out or clone it to a new base disk.

She couldn’t skip it. The VM would boot but corrupt data silently.

And Dave? He called her later that week: “You restored from a delta? I didn’t think that was possible without losing data.” restore vmware from delta vmdk

She had to restore from the delta —not the base.

If you have the delta and flat files but the .vmsd file (snapshot database) is corrupt or missing: Restore VM from flat and delta .vmdk files | VMware vSphere This is the safest method

She used a Python script with pyvmomi to read block pointers:

For most administrators, provides the highest success rate with the lowest risk of corrupting the original data source. Method B and C should be reserved for scenarios where storage space is critically low or attachment is not feasible. Always prioritize a file-level backup of the directory before attempting manual disk manipulation. The VM would boot but corrupt data silently

The previous admin, Dave, had taken a “before-upgrade” snapshot over a year ago. Then he’d left. And no one ever committed or deleted it.

If the descriptor file is missing or the "CID chain" is broken (ESXi cannot find the parent), you must manually edit the descriptor files. This is necessary if the VM fails to power on stating "The parent virtual disk has been modified."

When a snapshot is taken in VMware, the original base disk becomes read-only, and a new delta file is created to capture subsequent writes.

# Inside FinServe-07-000014.vmdk descriptor: RW 83886080 VMFS "FinServe-07-000014-delta.vmdk" parentFileNameHint="FinServe-07-000013.vmdk"