Maybe it's a bug

Hi melhem.

I suspect your connection string looks something like the following: 

            string strConnectionString = "[;];Authenication=Windows;Domain=K2Demo;User=test;Password=test;test";

If so, notice the [;] at the begining of the string.  The character contained within the brackets tells K2 how to parse the various parameters.  Thus if you change it to look like the following (with parsing on a comma): 

            string strConnectionString = "[,],Authenication=Windows,Domain=K2Demo,User=test,Password=test;test";

You should be able to successfully use passwords (or any parameters) that contain a semi-colon.  You may want to select a more obscure character than a comma in your actual code.

Hope this helps.

Bob 

It works

Thanks Bob for your help