How to solve "Unable to connect publishing custom string handler for output caching"

By Namwar Rizvi - Last updated: Sunday, January 11, 2009 - Save & Share - 9 Comments

If you are getting “Unable to connect publishing custom string handler for output caching” error in your event log then it is because of a custom web service you have installed on your Sharepoint server. Reason for this error is that you have a web part on your portal page which use the custom web service. Now, since Sharepoint uses output caching for the web pages to optimize the rendering experience and fast delivery of unchanged pages therefore, publishing infrastructure of Sharepoint tries to access the web service through your web part and due to any issue in your service, it starts generating this error.

Anyway, cutting a long story short, here is the solution:

Edit the web.config of custom web service (Please do not edit your Sharepoint Web application web.config) and make sure you have following under httpModules node which is located under system.web node. 

            <remove name=PublishingHttpModule />

Posted in Errors, Management • Tags: , , , Top Of Page

9 Responses to “How to solve "Unable to connect publishing custom string handler for output caching"”

Comment from tribecards
Time August 10, 2009 at 3:41 pm

Other than the error, does leaving the web.config file alone have any consequences? I mean, how does the error itself affect Sharepoint?

Comment from Marco
Time December 10, 2009 at 12:41 pm

Cheers, this was the solution that worked for me after a long long search.

I have BizTalk and SharePoint running on the same server and they both use the default website (I know, I should change this 🙂 Anyway, BizTalk’s Orchestration Port’s can be published as Web Services and even though I had the Process Worker Identities configured correctly (at leaast, I think), I still got this annoying error. I’ve added the following code to my web.config and problem was solved.

Comment from YOung Yang
Time December 28, 2009 at 5:04 pm

Dear sir,

I found your solution to fix Unable to connect publishing custom string handler for output caching. you said you have put a code to your web.config. I like to know what is the code? Please let me know and your help is greatly appreciated.


Young Yang

Comment from namwar
Time December 28, 2009 at 6:18 pm

Hi Young,
You need to edit web.config of your web service as mentioned above.

Comment from frevd
Time January 25, 2010 at 1:14 pm

cheers – thanks for analyzing the issue.

Comment from phil
Time March 24, 2010 at 9:06 pm

Thanks! One thing though: pasting the line above into the config file didn’t work for me because it didn’t like those kind of quotes. After replacing the quotes with standard ones it worked like a charm. Thanks again.

Comment from Dennis Cullen
Time April 23, 2010 at 7:44 pm

This solved a bunch of problems, thanks!!!

Comment from Waliullah
Time September 25, 2012 at 1:40 pm

Aoa Sir,

I was looking for the resolution of this issue and finds you while browsing 🙂



Comment from Dave
Time November 9, 2012 at 5:18 pm

Making this change crashed my web app.

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