I was using the default Trisquel 7,0 GNOME desktop and this also happened to
me. In my case, the cursor was black and in the screenshot it was white or
the other way around. For taking the screenshot I used gnome-screenshot.
I can't really help you with the update manager as I have really never used
it more than once.
- Re: [Trisquel-users] Update Manager Not Working tempaccount325