Error 25003. Error occurred while initializing fusion

The Microsoft .Net Framework 4.0 Setup may fail without any error message or the setup may crash during the install phase. You can find the below error message in the Setup log file (Microsoft .NET Framework 4 Setup_******_******-MSI_netfx_Core_*.msi.txt) under user temp folder(%temp%):

MSI (s) (18:60) [15:39:53:968]: Executing op: CustomActionSchedule(Action=CA_InstallAssemblyDef.3643236F_FC70_11D3_A536_0090278A1BB8,ActionType=1025,Source=BinaryData,Target=InstallAssembly,CustomActionData=C:\WINDOWS\Microsoft.NET\Framework\v4.0.30319\;C:\WINDOWS\Microsoft.NET\Framework\v4.0.30319\ISymWrapper.dll;78168)   
MSI (s) (18:00) [15:39:54:031]: Invoking remote custom action. DLL: C:\WINDOWS\Installer\MSI43B.tmp, Entrypoint: InstallAssembly    
09/16/13 15:39:54 DDSet_Status: LANGID: 1033    
09/16/13 15:39:54 DDSet_Entry: InstallAssembly started    
09/16/13 15:39:54 DDSet_Status: CustomActionData: C:\WINDOWS\Microsoft.NET\Framework\v4.0.30319\;C:\WINDOWS\Microsoft.NET\Framework\v4.0.30319\ISymWrapper.dll;78168    
09/16/13 15:39:54 DDSet_Status: No ProductCode was passed in the CustomActionData. Using the current ProductCode.    
09/16/13 15:39:54 DDSet_Status: ProductCode for assembly install/uninstall has been set to {F5B09CFD-F0B2-36AF-8DF4-1DF6B63FC7B4}    
09/16/13 15:39:54 DDSet_Status: Loading C:\WINDOWS\Microsoft.NET\Framework\v4.0.30319\fusion.dll    
09/16/13 15:39:54 DDSet_Error: Failure creating interface IAssemblyCache     
09/16/13 15:39:54 DDSet_Error: CreateAssemblyCache() returned -2147024703     
09/16/13 15:39:54 DDSet_Error: Error occurred while initializing fusion.    
MSI (s) (18:5C) [15:39:54:109]: Product: Microsoft .NET Framework 4 Client Profile -- Error 25003. Error occurred while initializing fusion.

The above error indicates that the Custom Action (CA_InstallAssemblyDef.3643236F_FC70_11D3_A536_0090278A1BB8) failed to install an assembly in the Global Assembly Cache. After debugging the issue, I found that dummy CRT file msvcr100_clr0400.dll was present on the system. The Microsoft .NET Framework 4.5 carries dummy versions of these CRT files (the files contain no executable code) for various compat reasons.

As per the installer log, the dummy CRT files were already present before the installation took place:

MSI (s) (18:60) [15:38:31:703]: File: C:\WINDOWS\system32\msvcr100_clr0400.dll;           Won't Overwrite;                Won't patch;      Existing file is of an equal version   
MSI (s) (18:60) [15:38:31:703]: File: C:\WINDOWS\SysWOW64\msvcr100_clr0400.dll;       Won't Overwrite;                Won't patch;      Existing file is of an equal version

I was able to resolve the issue by renaming the file msvcr100_clr0400.dll at the below two locations:


Comments (39)

  1. A Suresh Babu says:

    Thank you, Renaming solved my problem.

  2. Styve SIMONNEAU says:

    Thanks, this solved my problem i had during 12 hours !!! THANK YOU so much.

    Better than microsoft support.

  3. AlexM says:

    Thanks a lot. It realy works. Finally this problem solved. Thank you, Soumitra Mondal!

  4. MikeSF says:

    You are amazing…… 6 Hours of working on this and all better..

    Thank you.

  5. LarryB says:

    AWESOME!  After fighting with this for over a day.  This resolved the issue.

    Many MANY thanks!

  6. AntD says:

    Your'e a legend! {



  7. Orr Fabian says:

    Thanks!!!!!! You just solved me soooo much time!!! this should be posted in microsoft support!

  8. Srikanth P Vasist says:

    Thanks! It worked!

  9. maz bat says:

    Thanks, I was out of my wits to reinstall the .Net 4 after uninstalling .Net 4.5, It kept failing to install.

    You have saved me a great deal of time.

    Many thanks Soumitra Mondal.

  10. Satinder says:

    Awesome!!! That did the trick…

  11. Sarath says:

    Thanks…It worked…!!!

  12. Prakash Pandharkar says:

    Thanks..appreciate your help.

  13. Praveen says:

    Brilliant thanks

  14. Dan says:

    GREAT ! ! Worked perfectly !

  15. Gatmando says:

    Yes!!  Hours trying to figure this out. Brilliant and a big big thanks!

  16. archbishop says:

    It works perfectly! Thanks very much!!

  17. Roj says:

    THANKS! Luckily this was my first Google hit 😀

  18. aaa says:

    Awesome!!!!! Thanks very muck!!!!!!!!!!!!!!!

  19. Tom says:

    Perfect, this worked for me after a lot of time spent.  Thanks again

  20. Evgr says:

    Блестяще! Огромное спасибо!

  21. kaiwen says:

    Your'e a legend!


  22. omg says:

    Your'e a legend!  Thanks for you

  23. Li Kang says:

    it works, thks

  24. Serj says:

    Holy mother of god, thank you soooo much

  25. ftherese says:

    truly… this was the only real fix… I went through everything else listed in the microsoft help whatever.

  26. windy says:

    thanks very much    it solved my problem  

  27. Mike says:

    Two years later and this fix is still relevant. Much thanks!

  28. E says:

    Real ***! Thanks man!

    I was surprised, what so cheap trick is unknow to MS 🙂

  29. 这是一个来自中国的感谢 says:


  30. 中国网友 says:

    ohh,my god,it works,i try many 方法 on the net,you are a big god

  31. Hansjoe says:

    A great thanks from China…It helps me a lot~!

  32. Patrick N says:

    OMG :))) Thank You… after many framework fehler….this was help =))

  33. thanks says:

    thank you very much

  34. pan says:

    thank you so much!!! it's working!!

    1. zhou says:

      thank you,谢谢!

  35. AlexA says:

    Thanks! Finally after 8 hours of searching…

  36. dimos says:

    Thank you soooooo much !!!

  37. Ashley says:

    So AWESOME!! it solved my problem , which have troubled me for almost two months!!!. thank you very much ….!!! thank you!

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