I have several test profiles and most don't show any account or folders on the main screen (mail tab) with today's linux64 daily. Also the summary area on the right is blank and shows no email list. Only one profile seems to be working and showing all account and folders, but some account in that profile don't show emails when clicked.
I think I see normal stuff in imap:4 MOZ_LOG and "get messages" via menu produces a notification of new mail (but it never appears on the screen). There is no "get messages" button visible.
I've only tried and built the daily on linux so maybe OK on other OSes.
I see the problem on a daily I built locally, on a daily I downloaded from archive site ( 2023-01-21-01-03-47-comm-central) and on a try build derived from latest daily.
Not sure if related to the UI change I see with a "dark mode" at the top, search box at top and no "get messages" button etc.

I downloaded and tried other recent linux daily versions.
The last archived daily version that works is: 2023-01-18-10-06-38-comm-central
After that the UI changes and, as described, most profiles don't show any accounts and emails.

It may be broken for a bit - https://thunderbird.topicbox.com/groups/daily/T7df1556699d655bb
But hopefully better some time early in the week.

I've been pulling in incoming updates and rebuilding but, so far, no changes have resolved the issue (currently at c-c changeset c778318217b8...). So in case this might help, I observe this:

On the profile that DOES show stuff in the mail tab, I see at "View | Folders" that "All" is gray and checked. It can't be unchecked.

On the other profiles that don't show anything in mail tab, "All" is black and nothing is checked. If I select/check "All", nothing appears and "All" does not remain checked when I look again. But if I select/check "Unified" the unified folder view appears.

All profiles continue to work correctly with c-c changeset 76f62fd3a780... from 1-18.

Most likely duplicate of this bug 1812187.
Would you be able to load that patch and confirm?

(In reply to Alessandro Castellani [:aleca] from comment #3)

Most likely duplicate of this bug 1812187.
Would you be able to load that patch and confirm?

See no difference with the patch applied and after a "mach build".

Actually there is one difference. If I select "unified" I can't turn it off and it doesn't go back to all blank if I select "all" but remains in unified view.
I normally never use "unified" view but it seems like "all" and "unified" should be mutually exclusive, but I can put a check mark on both of them. Not sure if having both "all" and "unified" checked is a problem.
Edit: Never mine. Checked to 1-18 version and see you can have "all" and "unified" both selected. The "all" view appears down below after the unified view in the folder list.

Thanks for the info.
Folder modes are not currently fully supported and re-implemented.
We have some patches and fixes queued up for that area which should bring back everything as it was soon.

Do you see the message "Uncaught DOMException: String contains an invalid character" on the Error Console?

Yes I do. I see this with the patch applied:
13:26:21.028 Uncaught (in promise) DOMException: String contains an invalid character about3Pane.js:1697

I have some folder names with multi-byte UTF8 from testing imap capability "UTF8=ACCEPT" that I added a few years ago. However, I think they are all valid characters. At least they always displayed before now.

FWIW, I see this w/o the patch applied:
13:38:47.198 Uncaught (in promise) DOMException: String contains an invalid character about3Pane.js:1694

In both cases there are other things in error console. Let me know if you need to see more with or without the patch.

Ah, great info.
So probably a duplicate of bug 1812248.

Could you try applying this patch? https://phabricator.services.mozilla.com/D167774

(In reply to Alessandro Castellani [:aleca] from comment #9)

Ah, great info.
So probably a duplicate of bug 1812248.

Could you try applying this patch? https://phabricator.services.mozilla.com/D167774

I applied only the D167774 patch and not other one.
Yes, that fixes the main issue. I can now see emails on my main profile!

Great, thanks for confirming.
Marking this as a duplicate.