Clipboard not working from guest OS to main OS in VirtualBox

Question

virtual box

Main OS - Ubuntu 12.04 LTS
Guest - Windows 8.1
VirtualBox 4.3.2
Clipboard does not work from guest OS to main OS in VirtualBox.
The user in vboxusers is added.
A checkbox in the item: Devices -> Shared clipboard -> Bidirectional / From the guest to the main one.
extension pack installed.
Before that, I drove other versions of Windows on a virtual machine, there were no problems. Today I decided to try Win8.1

Answer 1

I didn’t meet, but most likely something was changed in Windows8.1 in order to “protect” the buffer and now you have to wait until VirtualBox is finished, or you can try to install some program to work with the buffer (or vice versa, remove it if it’s already).