Sounds like the previous email text is same colour as background. Please supply some info:

1. Menu app icon > Addons > Themes What theme are you using in Thunderbird ? eg: Dark, Light or 'Default - a theme with the operating system colour scheme or a theme you downloaded - what is it called?

2. When you click on 'Reply': what colour is the Text when you type and what colour is the background ?

3. Do you compose emails in Plain Text or HTML ? HTML will show the 'Formatting Bar' in a Write window.

4. Do you read emails in Plain Text or Original HTML? Check this setting: Menu app icon > View > Message Body as > What is selected?

5. What preferences are set: '5A' Menu app icon > Optons/Preferences > 'General' Scroll down to 'Language & Appearance' section 'Fonts & Colours' subsection click on 'colours' Post an image showing your current selections.

'5B' 'Plain Text Messages' subsection When displaying quoted plain text messages... Style: Regular Size: Regular - What is the selected colour - Black or White or something else ?

'5C' Menu app icon > Optons/Preferences > 'Composition' Post an image showing what you have in the 'HTML Style' section

Reply to Toad-Hall Sorry for slow response. No add ons or themes. Everything is plain default. Everything current. When I click "reply" the whole email (all replies back and forth) displays in blue lettering. But it is all highlited white. Background is black. When I try to type, on the bottom, everything disappears except the last reply and a blue line shows on left border of whole email but I cannot bottom reply. I need to click up to the last reply, which is all that shows now, and begin typing white on black background. Compose in plain text. Send in Plain text and HTML. Read in original HTML. (hmm)

Style "regular" Size "regular" color "White" Pics attached. Making any sense?? Thanks much Doug

first try in a non dark mode and see if that is the cause. The dark theme appears to be a little questionable at times.

Second image- Composition - shows you have selected 'Use Default readers colours' That means the background will revert to black.

Uncheck 'Use Default readers colours' then select email and click on Reply

Got the black text on white background. But just realized I see Friend's original post Then date and Doug Chadduck (me) wrote But nothing displays for what I wrote Then my friend's reply to that Then date and Doug Chadduck wrote But nothing for what I wrote. Etc.

He is not at all tech savvy so......... I'm confused It has worked fine for years but something within the last couple months changed and I've no idea what. I used to get reply reply to reply etc etc

re:Got the black text on white background. But just realized I see:

Friend's original post ----friend wrote in black font on white background. Then date and Doug Chadduck (me) wrote But nothing displays for what I wrote -- you wrote it in plain text using white font Then my friend's reply to that ----friend wrote in black font on white background. Then date and Doug Chadduck wrote But nothing for what I wrote. -- you wrote it in plain text using white font

So white font on a white background will not display.

Noticed you said: Compose in plain text. Send in Plain text and HTML. Read in original HTML. Style "regular" Size "regular" color "White"

change the plain text settings so you are typing in Black. Style "regular" Size "regular" color "Black"