Unable to remove host from vCenter

[timofcourse]

We have an existing ESXi 5.5. host we're unable to remove from a vCenter server environment. When attempting to do so we get the following error:

Remove host

<<hostname>>

Cannot complete operation due to

concurrent modification by another operation

We are able to add the host back to this vCenter environment as well as add the host to other vCenter environments. Further we're able to remove the host from those other vCenter environments. I believe the culprit is a VM thats reported as being orphaned on that host. This VM only shows as orphaned on the vCenter server we're unable to remove the host from, not when the host is added to other vCenter servers. When we attempt to remove this host the vCenter server we get this error on, all of the VMs on that host are removed with the exception of the orphaned one.

Any thoughts on how to resolve this before we open a ticket with support?

Thanks!

.

[HawkieMan]

I have a suspicion you have "dual" membership on this host, and have already registered it to a New vcenter. If that is the case you need to remove it from the New vcenter to Complete the removal from the old vcenter.

[timofcourse]

I've removed the host from the new vCenter server, rebooted the host and old vCenter server and reconnected the host back to the old vCenter server and still seeing the orphaned VMs. I was able to remove most of them following this KB, but sure enough theres one that just wont remove. In fact when I try to remove it it actually crashes my vCenter connection.

Also, not sure if it matters, but this orphaned VM only shows up in vCenter Server for this host. It does not show up when connecting to the host using the vCenter client directly. Ive also made sure there are no rogue files on this hosts datastore.

Any suggestions on how to remove this stubborn orphaned VM?

Im heading out for vacation for 2 weeks starting tomorrow so I may not reply until I return.

Thanks!

[Jimmy15]

There are two concerns

1. Removal of Host from old VC

2. Existence of Orphaned VM

let's start with Host

1. remove it from rest of other VCs

2. put it in maintenance mode.

3. reboot and add

Orphaned VM :

1. If VM still exist on Host, check if it really belongs to host. locate .vmx and add back to inventory then remove.

2. If VM doesn't exist on host ,check if this host holding lock of any .vmdk of this VM.

Regards

Pankaj