VB 7.0.4: Host key not active -how to fix ?

[LateJunction]

I can start a guest machine (Win 8.1) OK under Mint 21 with VB 7.0.4, but the Host key (Right Ctrl - has not been re-assigned) is not active so I cannot switch my mouse pointer to Linux. Consequently I cannot access the Guest Windows Devices Menu option, so I cannot install Guest Additions.

Is there a work-around. And what could have cause the Host key not to be active (it was with a previous VM, created on this Host, using Win 8 as a guest) ?

[scottgus1]

A 'failed' host key doesn't happen from a Virtualbox setting. Does this problem resolve if the host is rebooted?

Also try setting the host key to something else than Right Ctrl. Does the new key/combination work?

[LateJunction]

A 'failed' host key doesn't happen from a Virtualbox setting. Does this problem resolve if the host is rebooted?

Also try setting the host key to something else than Right Ctrl. Does the new key/combination work?

Thanks for the advice. I did set the host key to 'Left Shift' (incidentally the only option that I was able to set*); that re-assignment did not enable the Host key. While browsing elsewhere I saw a suggestion that the issue was with something intercepting keyboard signals before VB could handle them - and this proved to be the secret: back in VB Manger (which required a power-off to reboot my Linux host), I disabled USB access to my Logitech keyboard/mouse USB Receiver for that VM. This immediately fixed the problem.

* - Aha! Now I see how it works - smarter than me!