found more than one vmfs partition on disk

Hi Guys,

I was in a process of upgrading our blade server (Dell PowerEdge M610) from ESX 4.1 to VSphere 5.0 and after booting the server from ISO and I got the error message that Upgrade can't happen as system found more then onevmfs partition on the disk. I dont understand why this happen and how can we upgrade the server.

Any help be appreciated.

Hope to hear from you guys soon.

Thanks

Vikram