This may be a known problem in which an update appears to fail but actually completes behind the scenes
Please can you open a terminal by pressing 'Ctrl' 'Alt' and 'T' together.
Type or paste in this command followed by enter. This will refresh the update cache.
Code:
sudo apt-get update | tee ~/"$(date +"%Y_%m_%d_%T")-apt-get-update.txt"
Enter your password if asked.
Then enter this command which will calculate if any programs need upgrading and if so, it will ask if you wish to apply them.
You can answer 'n' if asked, we are interested in what upgrades the system reports being as required.
Code:
sudo apt-get upgrade | tee ~/"$(date +"%Y_%m_%d_%T")-apt-get-upgrade.txt"
Each command creates a text file in your home directory in which the screen output is saved.
After running the two commands please review the two text files and paste the results back here.
Thank you