virtualbox.org

I've never been able to figure out which programs require uninstalling before upgrading. I'm currently on 3.0.0 and am upgrading to 3.0.2 -- do i need to uninstall the 3.0.0 first?

You should not need to uninstall. I do because it is drilled into my head, but others say it works fine just to upgrade.

I keep the rule of minor versions: upgrade the current install, major version: uninstall previous install and install new major version. The latter would be when upgrading from 2.2.x to 3.0.x.

Running Windows Vista 64 as primary operating system.
I was using version 2.1.4, but upgrade to 2.2.0, 2.2.4, and 3.0.2 failed. Uninstall from Windows Control panel failed. Finally erased VirtualBox entries in registry and able to do fresh install of 3.0.2. But, I am now unable to use prior snapshots, getting error message (copy of log below):

"00:00:04.776 Changing the VM state from 'DESTROYING' to 'TERMINATED'.

00:00:04.839 ERROR [COM]: aRC=E_FAIL (0x80004005) aIID={0a51994b-cbc6-4686-94eb-d4e4023280e2} aComponent={Console} aText={Unable to restore the virtual machine's saved state from 'C:\Users\RDS\.VirtualBox\Machines\AMDVirtualXP\Snapshots\{183806db-7615-4475-b755-1ddbb86efa8b}.sav'. It may be damaged or from an older version of VirtualBox. Please discard the saved state before starting the virtual machine (VERR_SSM_LOAD_CONFIG_MISMATCH)} aWarning=false, preserve=false

00:00:04.839 Power up failed (vrc=VERR_SSM_LOAD_CONFIG_MISMATCH, rc=E_FAIL (0X80004005))"

Given my experience above, I am not particularly eager to reinstall 2.1.4. Is there any way to load snapshots from old version into 3.0.2?

In the 1.x series, I had to uninstall the previous. If I didn't, I'd end up with an odd mix of the old and new versions and it wouldn't work reliably. As of late in the 2.x series, I tried just installing over top of the old again and it's worked fine all the way through 3.0.2.