Home » Programming » .NET Programming » Windows 7 How to: Login failed for user ‘IIS APPPOOL\DefaultAppPool’

    If you obtain this error using WCF, IIS7, LINQ to SQL on Windows 7, read this thread:



    1. george says:

      Thanks man, it was very useful!

    2. Luis says:

      thanks!!!!!! hours looking for a solution and turned out so simple :)

    3. Nguyen Hai Duong from Viet Nam says:

      Thx alot :)

    4. Kautilya says:


    5. Haneef Abudulai says:

      Thanks a mill, bee battling with this for awhile now. That link helped, even thou it ain’t english :)

      Thanks :)

    6. mERGER says:

      Thanks!!!! I have been debugging for 2 days now! This solved it!

    7. [...] לעשות את התהליך הבא: (למעשה אחרי חיפוש בגוגל הגעתי לכאן שהפנה אותי לכאן – אבל היות שזה כתוב בשפה מוזרה שאני לא [...]

    8. Sumit thapar says:

      Hey Thanks a lot man really really helpful

    9. CDTRIX says:

      Thanks, A LOT..

    10. NicMartel says:

      Did not work for me.

      Error: Cannot open database “MyDB.mdf” requested by the login. The login failed. Login failed for user ‘IIS APPPOOL\DefaultAppPool’.

      If I change the DefaultPool Identity to LocalSystem
      Error: Cannot open database “MYDB.mdf” requested by the login. The login failed. Login failed for user ‘NT AUTHORITY\SYSTEM’.

    11. Mallikarjun says:

      thank u
      it really wrks
      please change the language so that it can be understood by all the viewers.

    12. Webliya says:

      thank you
      it works.

    13. zym says:

      nice! thanks

    14. pebuardi says:

      Thanks a lot.. It’s really solve my problem..

    15. While this may work, it causes a large security vulnerability. IIS worker processes should not have the access that the Local System account grants.

    16. Manoj says:

      when i try to open website in browser using IIS 7 in window 7 i faced the error loke “Login Feaild IIS APPPOOL/MyWebSite” and my database string pass in web reference dll so how can i solved it.
      please help me

    17. Shoh says:

      Worked for me

    18. NT says:

      GENIUS! Thank you for the info… it saved me hours of wasting time trying to do it on my own.

    19. blackblist says:

      Thanks !
      i have solved my problem !

    20. samuelanre says:

      thanks so much. spent a whole night figuring what could be wrong.

    21. Rema says:

      Thanks.. this helped alot…

    22. ThanhPhong says:

      Thanks, it’s helpful for me.

    23. Rajesh says:


      This information was very helpful. Things are working like charm

    24. Carla says:

      is there a way i can view this in english…sigh

    25. fahad says:

      Thanks dude it was useful!!!

    26. MikeM says:

      If you do it that way, you are not leveraging the new security features of IIS.

      I think the correct way to do this is to add an SQL login for IIS “APPPOOL\DefaultAppPool”.

      The reason MS stopped using NETWORK SERVICE or LOCAL SYSTEM is that there can be security issues between processes sharing the same account.

    27. James says:


    28. Thulani Mathenjwa says:

      Very useful thanx a Million $

    29. sarvin says:

      thanks it was useful

    30. Sheryar Nizar says:

      Its amazing. thanx

    31. Nikos says:

      Thanks!!!! I’ve been pulling my hair outfor the last 4 hours trying figure out what the heck was going on!!!!

    32. N says:

      Yeeeeeeeeeeeeees Tnx

    33. tienhoa82 says:


    34. Freddie de Beer says:

      Sure works!! Thanks man saved me time and debugging effort!!

    35. Donald Carl Kanyenda says:

      I had the Same problem but got the solution from this link


      hope u enjoying your coding

      Donald carl Kanyenda

    36. Anil says:

      Fantastic… Worked for me… Thanks a lot…

    37. Koen says:

      Super Thanks, after 1 week a solution that works in 10 seconds

    38. catherine says:

      thank you so muuuuuuuuuuuuuuuuuuuuuuuuch!!!!!!!!!!!!!

    39. sri says:

      boss u r a STAR thanks a lot man i was struggling with this almost a day man u r a star

    40. farzad says:

      Thanks this is very useful

    41. bin says:

      Thank you very much!

    42. Hamed says:

      God Bless You

    43. joy says:

      Awesome! saved me time.

    44. vivek says:

      thanks alot

    45. 1 says:

      Url not working …

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