We recently built a new vCenter 4.1 and migrated all of our ESX 4.0 update 1 hosts from our old vCenter server (4.0). Since it's a new vCenter server and name, I figured that I had to update the entries in snapdrive to point to the correct vcenter/esx server.
I went ahead and updated the hostname and left the account info the same since it's an AD account, after clicking OK, the MMC freezes and displays a popup "This snap-in is not responding. I have to kill the mmc to make it go away. This was tried on a vm machine running W2K3 with SD 6.2. When I went back into SnapDrive and try to reconnect, i get a "Object reference not set to an instance of an object." I ended up adding the netapp controller informatino back into snapdrive and now it appears to be working normally.
I have a few other vm machines with snapdrive installed and i'm hesitant on making the changes until I get a better understanding of what is happening, but it's something that has to be done since the old vCenter server is no longer in production.
I've made exactly the same experience with SD 6.3 and vCenter 4.1. Something seems to be buggy with this VC integration feature since the settings also disappear from time to time. I'm still trying to reproduce the behavior.
As an alternative to the GUI, the connection to vCenter can also be made via CLI: sdlci vsconfig set -IP <VCenterhost> -user <user> -pwd <password>
I reinstalled SnapDrive and during the reinstall process i specified the new vCenter server name. Everything appeared to work fine using the reinstall process to change SD integration with vCenter. Hope this helps.