After upgrade to 1.5.5a admin login no longer possible

[weif]

After upgrading to 1.5.5a from 1.5.4 it was no longer possible to log in to the site admin. entering what should have been a correct username and password resulted in the login screen being brought back up.

The 'forgot password' link takes you to a form to enter an email, but I am unable to find any evidence that an email was sent.

There is not a failed login recorded on the admin account record in the database. There is no log in the zen-cart log folder, and there is no error in the server logs...

any ideas? Any specific information needed that isn't included here? I know an error would be great, but there doesn't appear to be one recorded anywhere...

[DrByte]

When there's no message on-screen saying anything about a problem, that typically means PHP couldn't start a "session" (which is how it remembers you from page to page after login).
Often this is caused by damaged cookies in your browser, a changed directory path to your store, or a misconfigured server.
This FAQ may help: I can't stay logged in to my Admin area -- or -- PHP Session Handling isn't working for me.

[marton_1]

Don't know if it is connected but the first time I wanted to log in to my upgraded 1.5.5a it would only work with the Admin user name "Admin" - then it ran the Db update (only) and after that all the Admin names worked?