I have a custom master page using a few JS utilities like jQuery and skel.js that has been experiencing some errors whenever the page loads. The errors are transparent to the user, but show up in dev tools. The first one is from the "ScriptResource.axd" file and says "Sys.InvalidOperationException: The PageRequestManager cannot be initialized more than once." The second error is from "jQuery-1.7.2.min.js" and reads "Could not complete the operation due to error 80020101."

I've googled around but can't find answers that make much sense to me (I'm not a JS or Ajax expert by any stretch of the imagination) because they're all for other proprietary programs/sites, so if someone could either explain it to me in SharePoint terms or point me to a resource that can help I would greatly appreciate it!

  • 1
    did you ever find any solution to this? I'm running into basically the exact same error. Commented Mar 7, 2016 at 16:15
  • I didn't (Derek's answer didn't reveal anything in my case), and I actually don't have access to that site anymore to explore it. Ultimately I had to stop chasing it because more important matters took precedence. If your situation is different at all you might try posting a new question and link to this one.
    – thanby
    Commented Mar 7, 2016 at 19:13

1 Answer 1


It's really hard to say exactly what the issue is without seeing the code, but generally the PageRequestManager error is caused by having more than one ScriptManager on the page. It could be that there's one in the master page and one in a page, page layout, or web part. It could also be that some third party component is loading a ScriptManager behind the scenes. But every page load should have only one ScriptManager.

And I'm going to guess your second error is related to the first.

Open up your favorite browser's debugging tools and search through your code for Sys.WebForms.PageRequestManager._initialize(

If you find it in two places, there's your culprit. The parameters passed into the function in each case should provide a clue as to the origin of the superfluous ScriptManager.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.