Error Messages:

Notice: Use of undefined constant _MB_SYSTEM_REMEMBERME - assumed '_MB_SYSTEM_REMEMBERME' in file /modules/system/blocks/system_blocks.php line 98

Notice: Use of undefined constant _US_REMEMBERME - assumed '_US_REMEMBERME' in file /user.php line 56

Deprecated
'/class/mimetypes.inc.php' is deprecated, use '/include/mimetypes.inc.php' directly.

Story:

This problem occurs randomly when a user tries to login. It doesn't happen always. I've got many complaints from my members, that they couldn't login to the system and i've replied them it could be because of cookie settings of their browser.

Today, that happened to me either and i've logged in from another browser, turned on the debug mode, then tried to login from the first browser that didn't log me in again, and i got the error message above.

Investigation:

As an investigation, it seems it mostly happens when a user opens the browser when the pc didn't finish the startup issues yet and still running for them. I'm not sure if this is just a coincidence or the reason of this problem but it is a guess.

Additional Information:

And i think this is important here : The template i'm using does not have a "Remember me" checkbox.

Kind regards

I've removed the rows which use those constants from those files. In any case, i don't need them. I hope this will help.