I downloaded trial Exchange 2010 VHD machine and tied to run it in VirtualBox 4.x (in Ubuntu 11.04 64 bit).
At first it worked fine. But after few reboots (requested by the machine) I now see solid blue background after login. However, if I press Ctrl-Alt-Del I can see Task Manager, and can run some programs from it's Run dialog. For example, I can run cmd.exe, services.msc, and even Exchange shell. But when I run iexplore.exe or explorer.exe I see nothing, though the processes appears in the processes list.
I tried to run in Safe Mode and there after login I can see desktop, but after few seconds it reboots without warning.
Installing Guest Additions does not help.
What can be the reason? This is a very strange error.
UPD: Hm, during the second attempt while I was installing the Guest Additions again (in newly created machine, after I tried misc programs - i.e. after long time being logged in) - suddenly the desktop appeared. I wonder if it takes Window 2008 R2 whole 10 minutes just to show desktop.
