Original Article from : http://tech.eternj.net/2012/07/trendnet-kvm-and-vmware-problem/
I have a Trendnet TK-207K 2 port USB KVM attached to two computers, one of which has VMWare Workstation on Windows 7. When I am running the VMWare Workstation, the Trendnet kvm suddenly switches to the next machine. It is as if I hit scroll-lock twice to go to the next machine, but I didn’t. Then I have to manually press the button on the top of the kvm and wait for about 20 seconds for it to be re-recognized by the computer running VMWare. Very annoying!
I think the reason why this is happening is: when I’m using VM workstation and I set a num or caps lock status inside a VM and then leave the VM, my Num or Caps goes off and then goes on again when I enter the VM. So something is happening when the VM enters the virtual machine to set the Num and Caps lock, and I’d assume, the Scroll lock status too. If this is done by VM workstation manipulating the keyboard buffer it might literally be “as if you hit scroll lock twice”
The solution I found: first thing, make sure you have installed the VMware tools in your image. If you use the Num Lock, Caps Lock or Scroll Lock make sure they are both set the same on your host computer and your VMware image. For the VMWare image, when the virtual machine boots up, hit F2 to enter BIOS to set the key status.
Another note from here: http://forums.whirlpool.net.au/archive/911658
Most KVM Switches will switch computers whenever they receive a Scroll-lock keypress twice within 2 seconds. Whenever you move your cursor in or out of a Virtual Machine, VMWare will send code to the keyboard to reset the state of the Numlock, Caps Lock and Scroll Lock keys. If you move your mouse into and then out of a VM within two seconds the KVM will see two Scroll Lock commands pass through it and switch computers. You will tend to get fewer unintended switches if you run your VMs in full screen mode. Another option would be to get a KVM that has a configurable hot-key sequence.
Note from: http://communities.vmware.com/thread/155701
I was having the same issue with a TrendNet (TK-407) and a way to get around it was to turn scroll lock on, on the VMware clients. This way switching between the VMware Console and my PC did not cause the double scroll key issue since I guess the scroll lock was already selected in the client.