Locked dpkg and Freezing Synaptic Manager

One possible cause of the freezing synaptic manager is that the /var/lib/dpkg program is currently locked by another process. Remember that the management of packages on Debian or Ubuntu Linux is exclusive.

If restarting the computing does not fix the problem, try this:

sudo fuser -vki /var/lib/dpkg/lock

This command effectively discovers and removes current process(s) that owns the lock to dpkg. Now run a configuration to dpkg:

sudo dpkg –configure -a

this command re-configures all the broken packages.

Finally it is safe to run package upgrade:

sudo aptitude upgrade