If I try to switch Movable Type 4 on my site to publish dynamically instead of statically, I get the following error message on all of my pages:


I've tried to actually edit the mt.php file, adding 'if (!function_exists("is_valid_email"))' statements, but it doesn't help. I have no idea what this problem is caused by and would appreciate any and all help.

Just wanted to confirm that this is happening to me as well on a new install of stable MT 4.01. I will report this to the feedback form at http://www.movabletype.org/feedback.html

Are you using any additional plugins apart from the default ones that ship with MT?

I did have some plugins installed, but all of them are disabled mostly because they're made obsolete by MT4. So the answer is "no, I don't have any additional plugins installed". MT manages to break like this all by itself.

Disabled or removed from the plugins directory, even though they are disabled they are still installed. SmartyPants & Markdown for example are now part of the core install and older versions can cause conflicts.

I have a "Markdown" folder in my plugins folder, but deleting (moving it elsewhere) that caused the following error:



Markdown is not enlisted as an installed plugin within the Movable Type administration.

If it is the version of Markdown that comes with MT4 it is OK and can be put back. Only if it was one of the plugins brought over from MT3 then it needs to be removed from the directory.

I can't say confidently where the Mardown plugin came from, but I've put it back and disabled dynamic publishing because I still get the above mentioned error.

I am also getting this error on an existing installation of MT. It was happening on MT 4.01, and after upgrading to MTOS 4.1 it is still happening. I have all of the standard plugins installed, but have also tried disabling all plugins to no effect.

Any ideas?