You run a Windows Presentation Foundation (WPF) Browser application in a Firefox Web browser. When the application reads or writes a cookie from the Web browser, the Presentationhost.exe application crashes and you receive the following error message:

System.ComponentModel.Win32Exception: Unknown error (0x105)

at MS.Internal.AppModel.CookieHandler.SetCookieUnsafe(Uri uri, String cookieData, String p3pHeader)

at System.Windows.Application.SetCookie(Uri uri, String value)

This problem occurs when the following conditions are true:

  • The version of the Firefox Web browser is not earlier than 3.0.

  • You have installed .NET Framework 3.5 Service Pack 1 (SP1) on the computer.


A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that is described in this article. Apply it only to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Customer Support Services to obtain the hotfix. For a complete list of Microsoft Customer Support Services telephone numbers and information about support costs, visit the following Microsoft Web site: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.


You must have .NET Framework 3.5 SP1 installed to apply this hotfix.

Restart requirement

You do not have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the
Time Zone
tab in the
Date and Time
item in Control Panel.

x86 version and x64 version

File name

File version

File size











To work around this problem, use the version of Firefox Web browser that is earlier than 3.0.


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

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