Flidas without installing

I don't see why not. Have you tried and run into any particular problems?

@ chaosmonk: Thank you for trying to help!

>>Have you tried and run into any particular problems?

Yes, I have.
And my attempts have always finished by receiving messages like these three:

! Username or password invalid
! Configuration could not be verified - is the username or password wrong?

Login Failed
Login to server imap.mail.yahoo.com failed
Enter New Pasword - Cancel - Retry

Icedove
Connection to server imap.mail.yahoo.com timed out.

Thank you for your time!

> Assuming that you are indeed typing your username and password correctly,<
No doubts about that!

> it's possible that the problem is that yahoo won't let you sign in with cookies disabled in Icedove.<
That's a possibility I hadn't thought about.

> Try temporarily enabling cookies in Icedove's privacy/security settings and see if you can sign in.<
I'll let you know how the pudding tasted after having followed your recipe.

Thank you very much!

I tried Trisquel 8 live session with one of my mail accounts.

Icedove works and sends mail. There's no problem with authentication. I think the only limiting factor is disk space (live session RAM disk: 4 GB, based on available memory).

I'd suggest you check again your settings, especially SSL/TLS (encryption) and compare them with your email provider's configuration.

I don't see why Yahoo's service should be a problem if it works when installed properly. It's possible some providers use non-standard portals or 2FA.

One trick would be to copy, compress and extract the hidden .icedove subfolder in your ~/$HOME which contains all messages and login credentials (from a hard disk installation, that is). I've successfully restored email accounts using tar balls. I use tar to transfer files in a compact package to make sure all files are included.

@ loldier:
Hello!
Thank you for trying to help.
Before chaosmonk's post I couldn't find the road.
Now, if I don't misunderstand you, the road seems to have branched out simultaneously in at least 5 directions:
1)The issue of the disabled cookies in Icedove
2)The disk space factor
3)The encryption settings (SSL/TLS)
4)The non-standard portals issue
5)The two factor authentication issue (2FA)

Because my IT knowledge is extremely poor and I don't find it easy to jump from one research road to another my plan is to continue my research in the first direction until the problem is solved or this matter is ruled out. In this case I will continue with the other research roads in the order we have both mentioned, unless I receive convincing arguments to change it.

@ chaosmonk:
Hello!
Because you said
> Try temporarily enabling cookies in Icedove's privacy/security settings and see if you can sign in.<
my first move was to seek for the privacy/security settings in Icedove but I couldn't find such a place. So I have now moved my research to Abrowser's privacy/settings place. Am I on the right track?

Thank you for your time

@ chaosmonk

Please forgive me for this belated thanks message but I have spent much of the time since your last post here trying to balance the bad news with good ones.

In spite of having achieved my goal the results have left me annoyed and bewildered.

The bad news:
1)Everything I described in my first post was done taking into account the recommendations of the pages you mentioned in your last post.
2)Endeavoring to balance bad with good news I left aside my original plan of an orderly and neat research of the causes that were previously mentioned here.
3)I plunged into multiple and chaotic parallel investigations

The good news: The problem seems to be solved.

The causes of my discomfort and confusion are:
a)I don't know who solved it or how it was solved.
b)I have lost the opportunity to better understand how the different factors that were previously mentioned in this topic are/were participating in the problem
c)I have been left suspecting there are/were other causes (that were not mentioned in the topic) but that could also be involved.

For better or worse, these have been the facts.

Thank you for your time and help.

Comments and questions from anyone are always welcomed.

Hello

All my attempts since Tuesday, 21 August, 2018 16:10 CEST (UTC+2) were made after having "allowed apps that may use a less secure sign-in method" to access my Yahoo account.

This means that before my first post on Sat, 08/25/2018 - 00:46 CEST (UTC+2), all my attempts had been made with this setting and all the other settings required (including those of https://help.yahoo.com/kb/SLN4075.html) in order.

Thanks for asking.

Sorry.
In my last post where I wrote

>This means that before my first post on Sat, 08/25/2018 - 00:46 CEST (UTC+2), all my attempts had been made...<

You should read

This means that before my first post on Sat, 08/25/2018 - 00:46 CEST (UTC+2), most of my attempts had been made...