Carl, sorry you are having trouble.

Does https://support.mozilla.org/en-US/kb/thunderbird-115-supernova-faq#w_why-are-the-fonts-still-too-large-or-too-small-after-i-changed-the-density-and-font-size describe your issue?

Please post a screen shot.

Wayne Mery, The information you sent me to fix this problem has not helped me because I don't have the experience with selecting which clicks I should use! Is there any way you could contact me to set up an online session? Thank you for your help! Carl

Best advice is print the instructions. And use a pen to do each item in ...

1. the steps at "To reset layout.css.devPixelsPerPx directly to the supported default value" 2. the steps at "To reset mail.uifontsize directly to the supported default value"

Hello Wayne Merry, Unfortunately I have not been able to fix this issue because I don't have enough experience with this Technology! Please, if you know someone who could help me, don't hesitate to ask him/her to contact me. Thank you very much! Best regards, Carl

Hello Wayne Merry, Unfortunately I have not been able to fix this issue because I don't have enough experience with this Technology!

No one on this forum has any idea who you are or where in the world you live. So it is a particularly poor place to seek recommendations for a computer technician.

Ohhh, I wish you had asked me... I live in Victoria, British Columbia, Canada. And Mozilla can confirm to you by my email address since I purchased the Relay Premium on 10/19/2023 for an amount of $13.30 and their Invoice No. was: 4C121C51-0008. I have been cooperating with them for many years! Feel to check me out with them. I have been using Thunderbird for over 30 years and never had any problem of this nature before today, so please do your best to identify me through Mozilla so that you can trust me! Cheers, Carl

I suggest you let Google make the recommendations for assistance https://www.google.com/search?client=firefox-b-d&q=computer+technician+Victoria%2C+British+Columbia%2C+Canada.

Or even consult the yellow pages for a computer technician.

I have been using Thunderbird for over 30 years

Yet the email client we know as Thunderbird first came out as Minotaur 0.1 on July 28, 2003.

This is a support forum and nobody here does one on one support by phone, email or chat.

However products like Relay premium and Mozilla VPN you may get more direct support because you well paid for the products in subscriptions