If using version 68*:

• Menu app icon > Options > Options > Advanced > 'General' tab
• click on 'Config Editor' button to open 'about:config'

It will say be careful :)

If using version 78*:

• Menu app icon > Options > General
• Scroll down to the very bottom
• click on 'Config Editor' button to open 'about:config'

It will say be careful :)

• In search type: pixels
• Look for this line: layout.css.devPixelsPerPx
• Double left click on that line to open the 'Enter string Value' box so you can edit the Value.

The default value will be -1.0

• Enter a new number eg: 1.25 or 1.5 or 2.0 or 2.2
• click on OK

the effect is immediate, so you can modify that number until it looks ok for you.

I've included an image as a guide. It is from version 68.11.0, but all the about:config info is identical.

Dear Toad-Hall, it worked like a charm. I can read now :)

Thank you for your help! The detailed explanation you gave really helped a lot.

I have the same problem. I have used the method suggested here and the font size of the message list has changed but the line spacing between emails on the list remains the same. I had previously tried the userChrome.css approach to modifying the threads pane and was also able to change the font size by setting a value for the font-size property but neither the line-spacing, nor the bottom-padding, nor the bottom-margin CSS properties had any effect.

I have the same problem with TB 78.2.2.

I'm running OS X 10.11.6

My version of TB 78.2.2 is missing most of the preferences, including "Options," shown in the image Toad-Hall attached.

I'd like to roll-back to the previous version of TB. But in the interim, as I figure out how, at least I can make the Folder and Thread panes headings larger.

Does anyone know how I can get the rest of the Preferences working?

I've included an image to show the difference between Toad-Hall's example and what I have.

Many thanks in advance.

IngT re :My version of TB 78.2.2 is missing most of the preferences, including "Options," shown in the image Toad-Hall attached.

That's because the image I posted was version 68* and not version 78*. I mentioned 'Options' because I was talking about Windows OS and you are using a MAC OS so instead of 'Options' you would find it under 'Preferences'.

Thus: Menu app icon > Preferences > General In your supplied image you have already shown that you have located 'General'. Yes they decided in their wizdom to lump almost everything under 'General'.

So if you read the information as included in the 'Chosen Solution' you will discover I mentioned where you would find it under 'General' in versions 78*

Scroll down to the very bottom and in bottom right corner you will find 'Config Editor' button.

Thanks, Toad-Hall, for the clarification.

I also suffer with the miserly small font, have tried solution above but it just expands / contracts the borders. Wondering if this is an issue TB has with Linux as my PC is currently a Linux Mint 19.3?

This post made my day! I was just getting ready to try a different email program because the inbox fonts are so small and my eyes are too old to read that tiny print. Then I thought, there must be a way to change it so I ended up here on the support page.

I was a little hesitant to change it. I'm an octogenarian and always worry about messing things up. But, I decided to try using the post suggested anyway. It was so easy to follow the steps! Very good instructions! It worked perfectly! I can now see my inbox menu. Thank you so much!!!

Toad-Hall - thanks for this! It's the best solution so far! I get serious eye-strain if I spend much time going through the message list, hence the reason for fiddling with this. I've had to zoom my entire Mac screen (50" UHD) just so I can read my email lists!

BUT... I notice that the font for the folders list is larger than the message list. Unfortunately, I'd rather it be the other way around - this way, my list of folders doesn't fit. Also, the spacing on the message list gets too big compared to the font. Sigh.

Is there any way to control this independently?

In any case - best solution so far, especially since upgrades keep breaking add-ons - thanks!

You're solution works great! Can't thank you enough! Now I can still use this emailcliënt.