Hi,
First excuse me for my little english...

i installed k2 on my joomla , i have front end editors and i want restrict editors to access to media manager from front-end.
help me please...

1- How can i restrict front-end editors to access to media manager?

or

2- How can i disable k2 media manager and back the media manager to joomla original media manager?

thank

Hello,

You can change the editor for the frontend users in order to hide the media manager.
You can override the itemform.php as well in order to hide the browse server button.

I hide the browse button but i want to restrict user to access the media manage

This solution that you said is good but someone can enter the media manager from paste the media manager address to address bar

Hmm since you cannot trust your editors why don't you block all these URLs using your .htaccess as well.
I think this is a more bulletproof solution.

Yes, you're right , i cannot trust my editors because i made a ads manager website with k2.

and registered users can add their ads with k2 component...

Ok, then hardcode a 301 permanent redirect or a 403 (forbidden access) to all these URLs, and strip your itemform.php of all the elements you do not want to be accessible by your editors.