SharePoint Intermittent 403 Forbidden Errors

I recently encountered intermittent 403 Forbidden errors on a Windows SharePoint Services (WSS) site.  Most of the site would work, but when users accessed certain functions such as uploading a document or adding calendar items, they would receive a 403 forbidden error.  The problem appeared to be intermittent, however I was able to identify a pattern to the behavior.  If an administrator accessed the feature that caused the error, subsequent requests from non-administrators would succeed.  This behavior is typically associated with lack of permissions to the temporary folder where Asp.Net assemblies are Just In Time compiled.  To troubleshoot the issue, I used the filemon utility. 



Filemon identified that the w3wp.exe was attempting to access the /bin directory in the context of the requesting user account through impersonation.


A quick check of the bin directory permissions revealed only administrators could access the bin directory, so the solution is to add server\users Read & Execute, List Folder Contents and Read permissions.

Comments (37)

  1. Thanks,

    I had this problem on some wikis after a system restore/reinstall.


  2. Da says:

    I was having this same issue with a 2 FE WSS 3.0 farm.

    I verified that users did not have that access on the bin directories for my web sites, and added it.

    So far so good

    Awesome John, thanks!

  3. Lion King says:

    I encounter similar problem. The solution you mentioned works fine!

    Thank you!!

  4. DM says:

    Worked for me too on one of my customers case. Thank You!!

  5. Stark says:

    Thanks a lot for this, I was pulling out hair trying to solve this, didnt know where to begin. You saved my life.

  6. Srivatsan says:

    I have the same issue. But i dont know why it is a permission issue. There are certain pages that work and there are some that dont. And all of them are using the same DLL.

    My scenario is that i have custom ASPX pages that i have put into a Sharepoint site. If the Admin logs in then it works fine. But if a non-admin logs in then it throws the 403 Forbidden error. Please let me know if there is anything else i am missing.

    I dont know if i can add all the users and give them read access to the bin.

  7. Srivatsan says:

    As you have entioned in your article, if i ive permissions to the folder containing the web config then the application works. But why should i give this? Is there any other way of tacklng this?

  8. Raveekumar says:

    Thanks a lot. It is worked fine for me.

  9. Claude says:

    Thanks for the solution.  One of my SharePoint users in Canada has been really frustrated with this problem.  I kept giving her additional permissions in SharePoint, added her to higher level sites, and it would appear that I had fixed the problem.  However, the next day it was back again.  Your explanation helped me understand why it was intermittant and the changes to the permissions on the bin folder fixed it.

  10. Filda001 says:

    Great Solution, I was concerned for several weeks. tried everything possible but had not idea about FileMon….


  11. Yorick says:

    Hi John,

    Some developers of ours also ran into the same issue. Although the mentioned solution works, I am wondering why this is occuring with some web parts and are others working just fine. Were you using impersonation in your code when you had to configure these permissions?



  12. Tim says:

    Thanks so much for this – worked a treat. Excellent work!

  13. Bryan says:

    This post keeps on giving.  We just created a new test environment and this was the missing piece to our puzzle.

  14. Thomas says:

    Ahhh, thank you…  You have saved me many calls from a customer with exactly the same problem!!

  15. Jason Hooper says:

    The post just gave again.  Thanks so much.

  16. DM says:

    This is just awesome. 3rd time worked for one on my customer..:)

  17. Jameel says:

    Worked for me too after a sharepoint move to a new server farm. Thank you.

  18. JJ says:

    +1 on the above solution for a WFE that was recently upgraded from 2.0 to 3.0 using the in-place upgrade path.

  19. OsFoEl says:

    I hope this can help me.

    Thank you for your post.

  20. Kunal Patel says:

    You are a godsend.  I have been trying to find out what was causing this error for over 3 months now.  I was doing it in my spare time and kept authenticating as admin so all the users could upload.  As soon as I changed the permissions on the bin file, users could upload with no issues.

    Thanks a ton.


  21. chaholl says:

    Wish I’d found this post this morning!


  22. Suresh Kumar V.C says:

    Sir, Thanks for sharing your valuable information,,,you know this is why Microsoft rules the market,,,Thanks buddy

    Suresh Kumar V.C

  23. Suresh Kumar VC says:


    I applied these Access Control on the bin folder, but still getting the same errors. Any advise please,

    Thank you,

    Suresh Kumar V.C

  24. robmcm says:

    Dude – this nailed the issue that I was seeing when using SharePoint with Forms Authentication. (I thought that it was any number of other things causing it.) A million thanks.

  25. jenitta says:

    Many thanks for such informative post.I am happy to knew about it.…/requested-page-cannot-be-accessed.html

  26. Shiv says:

    Thanks a ton…it was bugging me since yday..your post rescued me 🙂

  27. Juan Peláez says:

    Thks men, It was driving me crazy. My situation was TFS 2010 running scrum templates, users were unabled to add documents or create items, with your solutions it is working now.

  28. Neil says:

    Worked like a charm, I had to download Process Monitor as filemon is not available anymore but it found the access denied problem on the bin directory.  Only problem is now I have Process Monitor I see there are a lot of other issues that need to be looked into.

    Thanks for the information, saving a bunch of time trying to find this by myself.

  29. Si says:

    this had me foxed for a while, suddenly happened on just one page!

    This has done the trick for the moment.


  30. Harry says:

    This looks like a great thread. We are having the same issue for certain users accessing SP2010 team sites. Has anyone had the same issue. It only seems to effect certain users.

  31. You're a hero says:

    Unreal that access to an empty directory will fix this.

  32. Ken says:

    Thanks – this seems to have fixed my problem

  33. TSG says:

    Many thanks for this,  saved me a lot of time!!  Could not understand why this issue was occurring,  this solved it for me.  thanks!!

  34. Kevin says:

    Many thanks. I have been pulling my hair out.

  35. amd kh says:

    Thanks – after 3 weeks , this seems to have fixed my problem

  36. Calvin says:

    Wow thanks after struggling with these 4 2days I found this great help