Hello Steven,

Did you create global mutex?

---
WBR,
Michael  Nemtsev [.NET/C# MVP] :: blog: http://spaces.live.com/laflour 

"The greatest danger for most of us is not that our aim is too high and we
miss it, but that it is too low and we reach it" (c) Michelangelo

SK> MutexSecurity object as a parameter. The interesting thing is the
SK> following statement from the MSDN documentation:
SK>
SK> If the named mutex has already been created with access control
SK> security, and the caller does not have MutexRights.FullControl, an
SK> exception is thrown.
SK>
SK> I wrote two test programs. The first runs as an Administrator and
SK> calls the constructor with a MutexSecurity
SK>

Hello Steven,

SK> I wrote two test programs. The first runs as an Administrator and
SK> calls the constructor with a MutexSecurity object that contains an
SK> Allow rule for 'Everyone' with MutexRights.Synchronize |
SK> MutexRights.Modify. The second program runs as a normal user and
SK> also calls the constructor. Based on the MSDN documentation I would
SK> expect an exception when the second program runs, but it works fine.

Could your refer to the documentation which implies this?

See MutexAccessRule class sample

what is u doing just allows user to have access, not block the user

       // Add a rule that grants the current user the
       // right to enter or release the mutex.
       MutexAccessRule rule = new MutexAccessRule(user,
           MutexRights.Synchronize | MutexRights.Modify,
           AccessControlType.Allow);
       mSec.AddAccessRule(rule);

---
WBR,
Michael  Nemtsev [.NET/C# MVP] :: blog: http://spaces.live.com/laflour 

"The greatest danger for most of us is not that our aim is too high and we
miss it, but that it is too low and we reach it" (c) Michelangelo