Security issue with FullTrust

Question

I have a .NET2.0 assembly on a network share for everyone to access. I've enabled FullTrust on everyone's machine for LocalIntranetZone.

However, on SOME machines (not all... that's the part that's driving me nuts) the app crashes. The error I get is below.

I'm completely stumped at this point. Any thoughts would be GREATLY appreciated.

Unhandled Exception: System.Security.SecurityException: Request failed.
   at System.Security.CodeAccessSecurityEngine.ThrowSecurityException(Assembly asm, PermissionSet granted, PermissionSet refused, RuntimeMethodHandle rmh, SecurityAction action, Object demand, IPermission permThatFailed)
   at System.Security.CodeAccessSecurityEngine.ThrowSecurityException(Object assemblyOrString, PermissionSet granted, PermissionSet refused, RuntimeMethodHandle rmh, SecurityAction action, Object demand, IPermission permThatFailed)
   at System.Security.CodeAccessSecurityEngine.CheckSetHelper(PermissionSet grants, PermissionSet refused, PermissionSet demands, RuntimeMethodHandle rmh, Object assemblyOrString, SecurityAction action, Boolean throwException)
   at System.Security.CodeAccessSecurityEngine.CheckSetHelper(CompressedStack cs, PermissionSet grants, PermissionSet refused, PermissionSet demands, RuntimeMethodHandle rmh, Assembly asm, SecurityAction action)
   at LoginRunner.Program.Main(String[] args)
The action that failed was:
LinkDemand
The type of the first permission that failed was:
System.Security.PermissionSet
The demand was for:
<PermissionSet class="System.Security.PermissionSet"
version="1"
Unrestricted="true"/>

The granted set of the failing assembly was:
<PermissionSet class="System.Security.PermissionSet"
version="1">
<IPermission class="System.Security.Permissions.FileDialogPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
version="1"
Access="Open"/>
<IPermission class="System.Security.Permissions.IsolatedStorageFilePermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
version="1"
Allowed="ApplicationIsolationByUser"
UserQuota="512000"/>
<IPermission class="System.Security.Permissions.SecurityPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
version="1"
Flags="Execution"/>
<IPermission class="System.Security.Permissions.UIPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
version="1"
Window="SafeTopLevelWindows"
Clipboard="OwnClipboard"/>
<IPermission class="System.Security.Permissions.UrlIdentityPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
version="1"
Url="file://xxx.xxx.xxx.xxx/data/Programs/Public/Misc/SomeApp.exe"/>
<IPermission class="System.Security.Permissions.ZoneIdentityPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
version="1"
Zone="Internet"/>
<IPermission class="System.Drawing.Printing.PrintingPermission, System.Drawing, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"
version="1"
Level="SafePrinting"/>
</PermissionSet>

The assembly or AppDomain that failed was:
Calrunr, Version=1.2.0.0, Culture=neutral, PublicKeyToken=null
The Zone of the assembly that failed was:
Internet
The Url of the assembly that failed was:
file://xxx.xxx.xxx.xxx/data/Programs/Public/Misc/SomeApp.exe

Answer 1

The problem is that the zone that's failing isn't your LocalIntranetZone, it's the Internet zone for some reason.

The Zone of the assembly that failed was: Internet

If it's only happening on some computers I would check your network topology because it sounds like some of your computers are trying to reach outside your intranet when running your app.