You called this product a "screen reader" which led me to think it was a text-to-voice tool. But I see it's a magnifier. Have I misunderstood?

Does the built-in magnifier tool provided as part of the Windows Accessibilty suite not do the job?

You can enlarge the text in Thunderbird.

First off all, I'd assume that the OS display scaling has been set to be as large as is useful or possible.

There are several ways to adjust text size in Thunderbird.

1) Users with high resolution displays whose text is too small have reported success using a configuration setting. http://kb.mozillazine.org/Layout.css.dpi I understand this will resize everything in Thunderbird; menus, controls and message content. I recently switched to a machine that has 142 dpi, as opposed to the 96 dpi I'd been using previously, and this adjustment worked well for me. There is a related setting, layout.css.PixelsPerPx which has a similar effect.

2) For message content, you can go to Tools|Options|Display|Formatting>Advanced and set the size of text in messages. http://xenos-email-notes.simplesite.com/417754775

For menus etc there is an addon, Theme Font & Size Changer. But recently it stopped working and while it has been fixed, I'd now be reluctant to rely on a tool that has a built-in expiry date and no guarantee it will be extended automatically.

3) Another way to set default font size, face and colours in both menus and message content is to set up two css files. We can come back to that if the easier options don't meet your needs.

Thanks for your response, Zenos -

Zoomtext is both a magnifier and a screen reader. As my friend went through the stages of his disease, magnification became less useful, so he needs the the text to speech function. I find Thunderbird a great email tool, and encouraged him to use it. He has used Outlook & AOL previously, but when using a web based system, the browser becomes. Outlook does a better job of reading text, but has other issues. I believe that if you contacted the engineers at Zoomtext, you will find that they have a problem which you can (hopefully) remedy. Ted

Ted, Zenos, like myself is just another user of Thunderbird.we are not developers and to be honest sometime our technical skills are not as good as they need to be.

If zoom text have problems, they are welcome to file bugs in bugzilla and get involved with the development folks (also mostly volunteers). Given Thunderbird is open source AND has an open extensibility programs via add-ons I would think the zoom reader folk should be able to actually either modify Thunderbird or get an add-on going that fixes their problem.

My guess is that they are not using the XUL windows Thunderbird does, instead being a wholly windows solution that can not see Thunderbirds windows and their paint events that a screen reader must access to confirm content changes. but without XUL, Thunderbird would not be cross platform.