FIX: Computer stops responding when the Mscorsvw.exe process starts in the .NET Framework 4


Consider the following scenario:
  • You install the Microsoft .NET Framework 4.
  • The .NET Runtime Optimization Service (Mscorsvw.exe) starts.
In this scenario, the computer performs slowly or stops responding.


This issue occurs because the Mscorsvw.exe process sets its service configuration to the Service Start Pending state. Therefore, the .NET Runtime Optimizer Service functions incorrectly, and this malfunction affects the performance of the computer.


Hotfix information

A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that this article describes. Apply it only to systems that are experiencing this specific problem.

To resolve this problem, 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 website:Note 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.


To apply this hotfix, you must have the .NET Framework 4 installed.

Restart requirement

You must restart the computer after you install this hotfix if the affected files are being used.

We recommend that you close all instances of Microsoft Visual Studio before you install this hotfix.

File information

The global 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.

For all supported x86-based versions of Windows XP, of Windows Server 2003, of Windows Vista, of Windows Server 2008, and of Windows 7
File nameFile versionFile sizeDateTimePlatform
Mscorsvc.dll4.0.30319.486334,67227-Jun- 201109:02x86
Ngen.exe4.0.30319.486150,85627-Jun- 201109:02x86
For all supported x64-based versions of Windows XP, of Windows Server 2003, of Windows Vista, of Windows Server 2008, of Windows 7, and of Windows Server 2008 R2
File nameFile versionFile sizeDateTimePlatform
Mscorsvc.dll4.0.30319.486334,67227-Jun- 201109:02x86
Mscorsvw.exe4.0.30319.486130,38427-Jun- 201109:02x86
Ngen.exe4.0.30319.486150,85627-Jun- 201109:02x86
For all supported IA-64based versions of Windows Server 2003, of Windows Server 2008, and of Windows Server 2008 R2
File nameFile versionFile sizeDateTimePlatform
Mscorsvc.dll4.0.30319.486334,67227-Jun- 201109:02x86
Mscorsvw.exe4.0.30319.486130,38427-Jun- 201109:02x86
Ngen.exe4.0.30319.486150,85627-Jun- 201109:02x86


To work around this issue, disable the Mscorsvw.exe process. To do this, follow these steps:
  1. Navigate to the following location in Windows Explorer:
  2. Run an elevated command prompt.
  3. Change the current directory to the following directory, type ngen.exe executequeueditems, and then press ENTER:
  4. Wait until you receive the following message at the command prompt:
    All compilation targets are up to date.
Note After you follow these steps, Windows Task Manager does not display an Mscorsvw.exe process.

More Information

The Mscorsvw.exe process runs in the background only when the following conditions are true:
  • The highest-priority assemblies have to be compiled after this .NET Framework redistributable is installed.
  • A .NET Framework application is installed to compile the .NET Framework assemblies.
Note The Mscorsvw.exe process usually precompiles high-priority assemblies within 5-10 minutes, and the Mscorsvw.exe process tries to process the low-priority assemblies when the operating system is idle.


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

ID článku: 2571181 – Posledná kontrola: 15. 8. 2011 – Revízia: 1