Well then boot to the console, log in as root, type apt-get update and apt-get dist-upgrade and finally type reboot. You got plenty of room on your hard drive? Anyway things should settle down shortly.
For the last year + synaptic has always stopped downloading on the last 1% or so of a large update, but has always
finished OK when re-applying the operation. I only mention it now, on the off chance the behavior may be a bug
perhaps related to this segfault, instead of my usb modem, or a dogy connection. Similar sized package installation
operations on the same hardware, using various Puppy linux package manager operations, complete the first time.