Two VirtualBox tricks

At the beggining of the year, I was told to try VirtualBox as a Virtualization solution for my personal needs (trying Linux, and having a few VMs for things like beta versions of software). After fighting with VirtualPC, and not being convinced with VMWare, I must admit VirtualBox is almost perfect: USB support, 3D acceleration (experimental and not for games, but its faster than software rendering anyway), almost every OS (whenever its a Linux or Windows)...

But sometimes is not as easy to use as the others, hiding actions that, at least in my opinion, should be clearly visible and easy to perform. The two most common ones are this two:

• Change UID of a VM: If you create a base VM, and copy the .vdi file, VirtualBox will complain that the UID is already in use. To change it on the copy, open a command prompt and execute (the executable is located in the VirtualBox install folder):
  VBoxManage internalcommands setvdiuuid xxxxxxx.vdi
• Mount a shared folder: To share folders between the host and guest operating systems, you have to use shared folders. But once you add one to VirtualBox, it doesn't appear, does it? Well, you have to mount it manually (under my PC), because it is a network share instead of a virtual drive:
  \\vboxsrv\xxxxxxxxxxxx

This are two actions you'll end up performing sooner or later, so I hope they prove useful!

P.S.: As an offtopic note, I'm going to PHP Conference Barcelona this weekend so if you're around and/or going just search for the Tuenti folks and I'll be among them :)