I've noticed that ever since the upgrade to v6.5.1, my laptop has had trouble hibernating.
It would just halt at "preparing to hibernate" and the disk would keep whirring.
After a bit of experimentation, I've realised that its not because of the hibernation processing screwing up, but the to the excessive harddrive activity after shutting down VMware.
The upgrade changed the way some harddrive options worked for the guest.
While the guest is running, any changes to the hdd would be kept in a "redo log" and processed when a snapshot is taken.
After running a guest for about an hour, this equates to ALOT of backlogged processing which takes a few good minutes to perform. Generally, a few good minutes which I dont have.
Luckily, it is quite easy to disable this feature.
Go to your virtual machine and make sure it is not suspended.
Edit the hard disk settings and go to "Advanced".
Click on "Independant" and ensure that "Persistant" is selected.
Save your settings and all should be well.
[ Source ]
No real instructions provided by the source, but it let me figure out where to look.