Clipboard isn't syncing after guest reboot (Windows 7 64-bit as host, Linux as guest)

I'm using Windows 7 64-bit as the host OS, and Kali Linux (32-bit) as the VM guest.

Copy and paste synchronization just stopped working all of a sudden in the Linux guest, but it works fine in the Windows guest. Is there any type of debugging I can do to try figuring out what's wrong? It was working fine until I rebooted the Linux guest... Not sure what's up with this.

Thanks for any help.