Viewing Folders

[ThunderbirdUser2]

Hello
I can no longer access the Inbox, Drafts, Sent and Trash folders on the left side of the mail window like I use to.
I just got my desktop back from being serviced and this is when this issue started.
Prior to sending the computer out for service, I could click on any of the above folders listed and the folder picked, would open and display what was in it.
Could switch back and forth between any of the four folders with no issues.
That is not the case now.

This is going to be a bit detailed in hopes of providing as much information needed for a possible solution.

Windows 7 Pro is the OS.
Thunderbird version 52.3.0 being used.
The folders are all visible, not hidden or missing.
No Add-ons being used.
The only Extension showing is Lightning and that must be a default Extension because I didn't add it.

When I open Thunderbird, I'm getting a window that I never use to get.
This window displays with the following headings and options for each heading.

Thunderbird Mail- My email address shows.

Email
Read Messages
Write New Mail

Accounts
View settings for this account
Create new account
Create new calendar

Advanced Features
Search messages
Manage message filters

I can't seem to get that window to stop appearing each time I open Thunderbird.
Before, the regular inbox mail window would open upon opening Thunderbird.
By regular, I mean the inbox window showing all received e-mail, etc.

Don't know if this new window is what's causing the problem with accessing the folders but, I never use to get that window.

From that window, I can access a folder and once I click on that folder, that's it, I can't do anything else with the other folders.
As an example, if I click on the Inbox folder(sorry if I'm not using the right term regarding folder), I can see all the mail in the Inbox and go back and forth between any mail that is in the Inbox.
But, once in the Inbox, I can't access the drafts, sent, or trash folders.
I click on them and nothing happens.

What I have figured out as a work around, is to right click on any of the other folders and pick "open in new window" for a particular folder and from that, I then can see what is in that folder.
So, If I want to see what is in all those folders, I need to have 4 windows open at the same time whereas before, I didn't need to do that.

I've tried for quite sometime now to figure out how to get things working like they were prior to today but, what I try, doesn't make any difference.
I even removed the Thunderbird program and reinstalled but, that didn't change anything.

I'm sure it's probably a simple solution to fix this problem but, I can't figure it out.
I've done many online searches for a fix but, no luck.

Any help would be appreciated.

[DanRaisch]

Things may simply have become "hidden." Try moving your mouse cursor to the left hand edge of the Thunderbird window until the cursor becomes a double ended arrow, then left click and drag the cursor to the right. It may reveal the folder pane. See the graphic representation provided by Daifne in this topic -- http://forums.mozillazine.org/viewtopic.php?p=3385323

[ThunderbirdUser2]

Even though the folders are not hidden, I tried your suggestion and still no difference.

[ThunderbirdUser2]

Just stumbled upon the solution.
When I switched Thunderbird to start in safe mode, that solved the problem.
That new start up window no longer appears and I can access the folders like I use to.

Until now, I didn't even know how to change Thunderbird to start in safe mode.

The computer shop must've changed a setting.

[ThunderbirdUser2]

Well, thought I had it fixed.
Turns out not quite.
As long as I don't close Thunderbird once it was started in safe mode, everything works like it should but, if I close it and open it back up, I'm right back to where I started.

I've disabled Lightning and I don't have any add-ons so, I don't know what could be causing this issue.

[ThunderbirdUser2]

Fixed now I think.
Had to check off a second option before restarting in safe mode.