Oh.. the vmsd file is corrupt.
Ack.. hopefully @a_p has ideas.
Btw, TS already has let me know via other means that the broken snapshot itself is not critical.
Please follow the steps from this post:
https://communities.vmware.com/t5/VMware-Workstation-Pro/Unable-to-open-file-vmdk-One-of-the-disks-i...
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Wil