If you cannot reconstruct the header, recover files directly:
In VMware environments, a virtual hard drive is actually composed of two distinct parts: a small text-based ( .vmdk ) and a large flat file ( -flat.vmdk ) that contains the actual raw data. Flat VMDK recovery refers to the process of restoring access to this raw data when the descriptor file is lost, corrupted, or when the flat file itself has been accidentally deleted. Understanding the Dual-File Structure