For no apparent reason, and with no warning, MT recently started refusing to let me log in. MT-medic didn't seem to help. I figured out how to get around the problem, however. Here's how:

1) Make a backup copy of the file app.pm in the
your-mt-dir/lib/mt directory.

2) Edit app.pm as follows: In the "login" subroutine, insert the code "return($author, $first_time);" between the last two "}" brackets that come right before the "## Login invalid..." comment. The code should now look like this:
...
}
## HACK debugging, make it return
## positively even if password did not
## match!!!!!!!!!!
return($author, $first_time);
}
## Login invalid, so get rid of...

3) After saving your changes, go to your login page and use your normal user name and any random characters for the password. MT should let you login.

4) Change your password in MT to something new and then logout.

5) Delete your modified version of App.pm and then rename your back-up copy of the file back to App.pm.

6) You should now be able to log in using the your old user name and your new password.

Worked for me, at any rate.

--Andrew
Blogging @ TheGantelope.com

sadly doesn't work for me,
get this error

'Got an error: MT/App.pm did not return a true value at lib/MT/App/CMS.pm line 13. BEGIN failed--compilation aborted at lib/MT/App/CMS.pm line 13. Compilation failed in require at mt.cgi line 21.'


?

mt medic problem-- report it in other post....

THANK YOU ajc, you just saved my day!! =)

it worked wonderfully for me with MT 2.661, as it honestly should with any programming logic I would think.

BWiese: Glad it worked for you.

Akciddento: Sounds like a syntax error. Misplaced ";" or "}" perhaps?

At any rate, this hack was for 2.661 and may not work with other versions.

I would like to add my thanks. The search actually worked and I found your post. After having mt installed for a month or more (this install) I suddenly, with no changes whatsoever, couldn't log in.
To say I was ticked is putting it mildly. I had visions of all my work down the drain. Luckily I found your post and it worked.
Yoou deserve a medal