Thanks for your very prompt reply. As usual I did not specifically state that for backup I use the following:
MY PASSPORT: MODEL WDBLUZ5000asl - 03. This is the external device I use for backup along with Time Machine.
This backup worked successfully until the past 2 or 3 months. After installation it reminded me of days since last backup & I believe backup (poor memory on my part) performed on a specified time. Now it does not remind me for a backup & when connected I must press “backup now”. Yes, I use “time machine” to refer to backups. Time machine will not activate My Passport.
I greatly appreciate the help to be able to restore to original conditions. I failed somewhere.
Thank you JM