Upgrade problem

I tried to check for updates. Error message:

E: Problem executing scripts APT::Update::Post-Invoke-Success 'if /usr/bin/test -w /var/lib/command-not-found/ -a -e /usr/lib/cnf-update-db; then /usr/lib/cnf-update-db > /dev/null; fi'
E: Sub-process returned an error code

Then I decided to try a fresh install. I downloaded the Trisquel 10.0 ISO file but the MD5 and SHA256 did not match. I am no expert, but I have never had this happen before.

Well, Synaptic Package manager came to the rescue.

The failed upgrade broke hundreds of packages. So I started Synaptic and went to Edit->fix broken packages.

This took a while and resulted in various warnings about Grub configuration, which I ignored.

Next step in Synaptic was to push the orange button "Mark All Upgrades" and "Apply."

It took half an hour for Synaptic to work its magic. It stopped a couple of times to ask if I wanted to keep or replace an old files. I opted to replace each time.

When Synaptic finished, the system was upgraded to Trisquel 10. Looks like everything is functional.

I rebooted and the system started perfectly. The Trisquel 10 artwork looks nice.

Now I can delete my downloaded Trisquel ISO which doesn't match the SHA and MD5. Not sure what is going on there, but I no longer need the ISO.

Thanks.