VirtualBox bidirectional clipboard sharing stops working after some time on a Linux guest OS

The linux one-liner:

pkill -f VBoxClient; VBoxClient --clipboard

A Windows powershell script.

echo "Trying to restart VBoxClient"

$vbox_process = Get-Process VBoxTray
Write-verbose $vbox_process
$procID = $vbox_process.id

if ($procID  -gt 0)
{    
    $cmdline = (Get-WMIObject Win32_Process -Filter "Handle=$procID").CommandLine
    Write-Verbose $cmdline

    Write-Verbose "Stopping VBoxTray"
    $vbox_process.Kill()
    $vbox_process.WaitForExit()
    Write-Verbose "VBoxTray stopped"

    Write-Verbose "Starting VBoxTray"
    Start-Process -FilePath $cmdline.Split(' ')[0]
    echo "VBoxTray Restarted. All Done"
} else {    
    Write-Warning 'Could not find existing vboxTray process. Launching direct?'
    Start-Process -FilePath "C:\Windows\System32\VBoxTray.exe"     
}

Note: powershell is not really my field of expertise, so I'm expecting some community edits here :)

How to fix shared clipboard in VirtualBox

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 clipboard should work afterwards.

I found out that on Linux guests (Ubuntu in my case) and Windows 7 hosts (I guess that doesn't matter) you just have to restart the following process on your guest machine:

/usr/bin/VBoxClient --clipboard

Find out the PID of the process with ps and kill it. Afterwards start the process with the above command again and the clipboard starts working again. I use this for example:

kill $(ps aux | grep '/usr/bin/VBoxClient --clipboard' | grep -v grep | awk '{print $2}')

/usr/bin/VBoxClient --clipboard

Try running vboxadd-timesyn start to restart the service.

One other thing that I remember reading was to change the clipboard sharing from bidirectional to host to guest.

Here you can find an old bug ticket that looks similar to your problem. It's a long read, but you may find some suggestions in there useful.

Finally, if nothing solves the problem, I suggest you to open a bug report in VirtualBox's Bugtracker yourself, because you are not the first one having problems with the shared clipboard.