If you can find it, SnapVMX script was always helpful to me to straighten out snapshot chain issues. VMWare support hooked me up with that one and it was used by them on our issues that kept reoccuring due to some less than stellar backup software.
Also worth mentioning - some of my fellow engineers relied a little too much on snapshots, making my datastores a complete mess. I ended up retrofitting a PowerCLI script to go through vcenter and identify which VMs had snapshots older than a couple of days. That script would be run via a scheduled task every day and email me a report...so I could yell at said engineers who had stuff kickin' around. It might be worth spending the hour or so getting that going.
Edit: See attached
The script won't necessarily do anything that those other commands can. It's just a handy utility to present your chain and identify any errors. I had used that in my old 4.1 U2+ environment without issue. I would always go into the properties of each VMDK in the chain and make sure the parent/child relationships were valid, making changes where they weren't set right. Most times I'd create a new snapshot once that was validated, I'd create a new snapshot, then delete all of them.
I dont' have access to the environment where I used these, but I've also included my troubleshooting method. Please forgive any newb-ness in the instructions or application thereof. I don't fancy myself an expert and just documented what I'd do to resolve the issues I'd encounter.
Message was edited by: Ytsejamer1 - Added snapshot script txt file and added notation.