shared clipboard intermittant failure

[quantsuff]

This is similar to ticket #5266, except host is Linux and Guest is Windows

VirtualBox 3.1.2 r56127
Host: Fedora 12 64-bit
Guest: Windows7 32-bit (single guest)

Guest additions install and guest rebooted afterword.
Shared clipboard copies work in both directions, the after a random number of hours,
Sometimes guest-to-host copying will fail
Sometimes copying both ways will fail

Attempted to restart the service in Windows 7 but failed. Should I be restarting something in Fedora?

Steps attempted in Windows client:
Recently when guest-to-host failed again I tried restarting
VirtualBox Guest Additions Service (system32\VBoxService.exe)

-Control Panel\System and Security\Administrative Tools
-Services
-Highlight VirtualBox Guest Additions Service -- choices are Stop the Service or Restart the Service

Click on either. You get this shutdown timeout message:

"Windows could not stop the VirtualBox Guest Additions Service service on Local Computer
Error 1053: The service did not respond to the start or control request in a timely fashion"

Now Service Manager shows it as having no Status (not running) and your only option is now Start the Service

Click Start the service. It appears to start, but guest-to-host clipboard is still broken.

[quantsuff]

OP: and restarting the VM is not a practical answer.
VMWare Server is looking better and better.

[quantsuff]

I opened a ticket on this
http://www.virtualbox.org/ticket/6150