Ctrl key doesn't work in Virtual Box, Linux host

Ctrl is not working in virtual box. When I use Ctrl+a/u/l/w etc., in Virtual Box Guests its acts as only a/u/l/w. any ideas regarding this.

my Virtual Box Version is 3.1.2 running under Ubuntu 9.10. i faced the same thing for windows, Redhat, ubuntu guests.

The issue relates to the System Setting >> Mouse and Touchpad >> "Show position of pointer when the Control key is pressed" option.

Simply disable this feature and the left Ctrl key will be available within all your VMs.

By default, VirtualBox reserves the right control key as the "Host" key. You can still use the left Ctrl key on every machine I've ever used. If you'd prefer to make something else the Host key (e.g. the almost-never-used Scroll Lock key), in the VB window click File >> Preferences >> Input and choose a different key.

I'm Using Windows 10 Host and Ubuntu 14.04. I solved the problem by Deleting the "Right Ctrl" key from the list of shortcuts reserved by VB. In the VB's menu got to:

File->Preferences->Input->VirtualMachine

||Name||Shortcut||
|Host Key Combination|Right Ctrl|

Delete this shortcut and that's it!