Ytdyklly

If your guest OS is ubuntu then running following two commands in ubuntu terminal should help:

$ killall VBoxClient

$ VBoxClient-all

In the Oracle virtual box setting go to

Settings > General > Advance

There is a an option Drag n Drop. Select the direction you want to copy the text.

For me, Windows 7 host and Ubuntu 16.04 guest, I had to install VirtualBox guest additions.

1. Start the virtual machine


2. Click Devices menu


3. Select Insert Guest Additions CD image


4. Change to the directory where your CD-ROM drive is mounted (typically /media/<user>/VBOXADDITIONS_x.x.x/)


5. Install it sudo sh ./VBoxLinuxAdditions.run
   


6. Reboot the virtual machine!

I found the complete steps in this link

Restart the VBox clipboard module:

pkill 'VBoxClient --clipboard' -f & sleep 1 && VBoxClient --clipboard

In Ubuntu you may need to install virtualbox-guest-x11

sudo apt-get install virtualbox-guest-x11

and then start virutal box client

VBoxClient-all

If needed, upgrade VirtualBox to latest version, currently 4.1.2, they solved many issues. Then reinstall Guest Additions on the VM, as copy-paste is managed by guest additions drivers.

How to fix shared clipboard in VirtualBox (Windows Guest)

1. In VirtualBox Windows Guest, Open Task Manager


2. Go to Processes Tab, highlight VBoxTray.exe and select End Process


3. Go to Applications Tab and select New Task


4. Browse to the VirtualBox Guest Additions installation folder and select VBoxTray.exe and select OK.

The bidirectional shared clipboard should work afterwards.

In Ubuntu 16.10 I had to run following command to get it to work:

service virtualbox-guest-utils start

Obviously, you addition to this, you need to set the Shared Clipboard setting to Bidirectional in General/Advanced Virtual box settings.

I use a Mac Host OS, and Ubuntu Guest (with lubuntu desktop).

Dmitry's answer got me so close! But VBoxClient wasn't running when I looked for it with ps, and trying VBoxClient-all failed:

$ VBoxClient-all

Failed to connect to the VirtualBox kernel service

Failed to connect to the VirtualBox kernel service

Failed to connect to the VirtualBox kernel service

Failed to connect to the VirtualBox kernel service

Failed to connect to the VirtualBox kernel service

Then I found
https://www.virtualbox.org/ticket/9332

Turns out, VirtualBox additions didn't launch automatically for some reason. Starting vboxadd manually allowed me to then run the VBoxClient with the clipboard enabled.

arin@arin-VirtualBox:~$ sudo /etc/init.d/vboxadd start

Starting the VirtualBox Guest Additions ...done.

arin@arin-VirtualBox:~$ ps -ef | grep -i vbox

arin      2687 22537  0 10:53 pts/1    00:00:00 grep --color=auto -i vbox

arin@arin-VirtualBox:~$ sudo /usr/bin/VBoxClient --clipboard

arin@arin-VirtualBox:~$ ps -ef | grep -i VBox

root      2693 22100  0 10:53 ?        00:00:00 /usr/bin/VBoxClient --clipboard

arin      2698 22537  0 10:53 pts/1    00:00:00 grep --color=auto -i VBox

And now copy/paste works!

My configuration is Windows host, Xubuntu guest. I guess it doesn't hurt to restart everything, but this is the client that matters. (VBoxClient-all is merely a script that runs /usr/bin/VBoxClient --clipboard and others.)

$ ps -fe|grep -i clip

tbc       1400     1  0 Jan18 ?        00:00:00 /usr/bin/VBoxClient --clipboard

$

$ p=1400;kill -int $p;ps -fp $p

$ /usr/bin/VBoxClient --clipboard

$ ps -fe|grep -i clip

tbc      30555  1281  0 13:01 ?        00:00:00 /usr/bin/VBoxClient --clipboard

$ pstree -sp 30555

init(1)---lightdm(1094)---lightdm(1261)---init(1281)---VBoxClient(30555)---{VBoxClient}(30556)

$

Note it runs in the background by default. It was owned by init(1), but when I invoked it, it got adopted through a tree I'm not familiar with.

I was using VirtualBox 4.3.12. Once I upgraded to 5.0 the latest, the bugs were fixed.

No combination of reinstalling Vbox additions helped.

Solution: always try upgrading to the latest https://www.virtualbox.org/wiki/Downloads

Login to your guest machine and open the CD drive where "VirtualBox Guest Additions" should be inserted.

Open this CD drive and execute the file "VBoxWindowsAdditions.exe".

After the installation you have to restart, then it should work!

On Ubuntu 18.04 running on VirtualBox 5.2.22 , I did the following:

1. On VirtualBox Manager, right click Ubuntu VM->Settings->General tab on left->Advacned tab on right.
   Now choose Shared Clipboard as : Bidirectional



2. 
   

   On Ubuntu, on the terminal run the following commands:

   
   
   

   
   

   sudo apt install virtualbox-guest-x11

   
   

   
   

Now I had to restart Ubuntu to run the below command run successfully:

VBoxClient --clipboard

After this, the bi-directional copy started working.

I had similar problems with VirtualBox 5.1.14. The computer was running Opensuse Leap 42.2 and a Windows 7 Pro (64Bit) was installed on the VM. Restarting Vboxtray.exe solved the issue once but finally deactivating the indexing service of Windows fixed it permanently.