Well I'm 55, not a guy and I've never meddled with your computer  :)

• What version are you currently using that works for you?
• What OS are you using?
• What type of mail account? Is it POP or IMAP?

Have you switched off updates or not? Tools > Options > Advanced > Update

Ah. I found a place to reply! the seeming inaccessibility of doing a back and forth is so frustrating. Answers: I am using Thunderbird 24.5.0. The 31s have lost all--or not transferred over--any info. Neither have they been able to download any new e-mails. Just a blank form. I have a new computer. It is on Windows 8.1 with a small program installed maybe Modern Mix? that emulates o.s. 7 or earlier. (It's not a touch screen, Toshiba's choice, so why should it have the series of tiles to choose) I have,now, gone to Tools and asked to be notified before T'bird tries to unload on me. This happened this morning. I declined. but looked to see what the update had. Now I have sent that window away. Seems one fix it didn't have is a problem with reloading old data. Fine. I guess I'm vulnerable until that is fixed. And yes, I do get messages thru e-mail that have the weird aE something symbols where there ought to be a ' or so.

Why am I asked to post a reply to the message I just wrote?

These postings are a conversation or dialogue. It's simply an invitation to the reader to join in (hopefully with a relevant and helpful comment, unlike this one! ;-) )

Character substitutions usually mean something is using one character set but telling a different one, or not telling us and making Thunderbird guess.

Try View|Character Encoding and see which one works properly. Maybe setting that one as the fallback would be productive.