All Products Support Forum

I use a MacBook Pro v. 10.15.7 (Catalina), and I live in the UK. I am going to upgrade my old MacBook Pro to a MB Air, and my Time Machine has stopped working. While researching a solution I found that perhaps there was not enough space on my HD to 'create a snapshot'. So in the process of deleting stuff in order to make space, I found lots of 'duplicates' in the Apps Storage section of the HD, I thought it was safe to delete them as the 'originals' would still be there (same date, same size). I now know I have been very ignorant/stupid (my dog died a few weeks ago and my mental health hasn't been the same since.) However, I was very mistaken and seem to have deleted a lot of my working apps, the most important of which being Thunderbird, which gathered my 4 different email accounts. I'm not sure what version I had last, as it has disappeared, but I'm pretty sure it would be the latest version. My latest download is 68.2.2 (20.11.19). So I tried to reinstall it, but came across this notification 'You have launched an older version of Thunderbird... Create new profile, or Quit.' I googled this but being a not-very-techy senior lady, I can't make sense of what I should do, my main concern being not to lose all my settings, my emails saved in folders, as well as being able to receive and send. I am sure I saw some reference in the past of a library which would contain the emails, but don't know what to do about this notification. The other problem, of course is that I can't completely rely on Time Machine as my last backup is dated 24.7.23. Thank goodness today is a Sunday as there should be less traffic on my email accounts (I am involved with lots of local activities, including being a community journalist). I would be so grateful if someone could help me navigate this minefield and reinstate my app so it works as closely as it did before. Many thanks in advance for your help and patience.