Do you have enough free space on the destination lun? I ran into this a few weeks ago, and I tried several things. I svmotioned about 14 servers to new luns, and I ran into a batch of them with this problem.
I tried 3 things in tandem, so I don't know which solved it.
1. Rebooted virtual center
2. Migrated the guests to other hosts, and rebooted each host
3. Kept a minimum of guests on the target host *
3 was the one I think was the trick....I didn't have enough memory for the snapshot of ram plus the ram in use....that's not exactly what I mean.... just can't say what I'm thinking--having drunk entirely too much scotch tonight.)
