Fatal error: Allowed memory size of 16777216 bytes exhausted (tried to allocate 4864 bytes) in /usr/share/squirrelmail/functions/mime.php(674) : regexp code on line 1

so, my logical answer was. mmm ok php needs more memory (memory_limit in php.ini), then i changed him but message still apear, so i take all my guns in google and got me at this place.

You need focus on next paragraph:

This error may also be caused by setting option $allow_server_sort to false in config.php

then i changed my config.php (squirrelmail) and works in flames!  please do it if you can! now inbox’s loaded too fast! believe me! try it!