Datastore 'datastore1' conflicts with an existing datastore in the datacenter that has the same URL (..) but is back by different physical storage

Hi,

I'm new to vCenter Server, so you can assume that I'm missing something obvious.

I've installed vCenter Server 5.5, and connected one of two ESXi baremetal 5.0.0 hosts successfully. When I attempt to connect to the second ESXi 5.0.0 host, I get the error message:

Datastore 'datastore1' conflicts with an existing datastore in the datacenter that has the same URL (..) but is backed by different physical storage

I have Googled this and found what I think are the top successful answers, but all seem rather unique in their situation (they have a cluster, I don't) etc. Some solutions involve disconnecting the datastore and rebuilding things. I'd like to not make things worse, and can probably live with using vSphere client (not the web client) until I can perhaps start over again with a 5.5 install of a new host once I back up everything from the unconnectable host. I have shut down all VM's on the second host. I've put in into maintenance mode. I've renamed the datastore, all to no avail.

Thanks in advance