Your system administrator does no allow the use of saved credentials
to log on to the remote computer <computername> because its identity
is not fully verified. Please enter new credentials.
If you are using Hyper-V and your client is in a domain you might have seen this dialog a couple of times.
Or if your testing out VMM 2008 Beta in a domain environment you must have gone nuts by now.
The workaround for it is pretty simple.
On your domain server, open up Group Policy Management Editor and go to Computer Configuration -> Administrative Templates -> System -> Credentials Deligation.
Double click on Allow saved credentials with NTLM-only Server Authentication, click Show and add "*servername.domain" to the list.
My server is named Exia and my domain is home.mindre.net, so I added *EXIA.home.mindre.net to the list.
Now go on your client and open a Comand Prompt with admin rights and run gpupdate.
Cached Credentials in a domain environment should now work :)