Let's try another approach and delve a bit deeper,
Boot up the recovery mode and choose the root access terminal. Be careful and sure of what you do here - you are ROOT . No mistake is forgiven or reverseble if it affects the system in particular.
What results with this command sequence(oldfred's methology) - ??:Seeing if cleaning and updates resolves the situation.
May have to (re)mount the "root" partition, I do not recall if it is initially mounted as read-only in this option.
apt-get autoclean # only removes files that cannot be downloaded anymore (obsolete)
apt-get update #resync package index
apt-get upgrade #newest versions of all packages, update must be run first
#would upgrade you to the latest kernel in the repositories
#dist-upgrade is also able to remove existing packages if required/and install held back packages,
apt-get -f install
dpkg --configure -a
All that does is update it again.
With the above done -one command at a time, awaiting results upon completion of each command: Reboot with terminal command: