InfoPath error & solution: InfoPath cannot open the following form … The file is not a valid XML document.

Yesterday I had a problem on a new SharePoint 2013 farm that took me some hours to solve it.

Problem:

I was not able to customize forms (again) using InfoPath on lists after creating them before sucessfully.

 

Steps to reproduce:

First I created a site collection and a custom list in it.

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Than I use the “Customize Form”  button in the Ribbon menu. The new form opens in InfoPath designer.

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Than I modify the form and publish it.

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In the  browser I verify it’s working.

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Than I want to change the form and click the Ribbon button “Customize Form” again.

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Now this happens:

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Error Message:

InfoPath cannot open the following form: http://sharepoint.local/sites/test/Lists/My New List/Item/template.xsn
The file is not a valid XML document.
DTD is prohibited.
Line 1, Position 9

When opening the URL of the InfoPath template in the browser I get this error from the Forms Server:

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(Normally there would be a download dialog.)

 

Solution

It’s so simple… 😉 – After some network, log and code analytics I could figure out that you need…

… a site collection at the web application root!

Remember the first screenshot above. There I showed you the possible locations for the new site collection. As you can see the root “/” is available. This means: There is no site collection at the web app root.

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After creating a site collection at the web application root I’m able to customize the list form with InfoPath. – After doing so:

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Problem solved 🙂

 

My friend and colleague Guido could reproduce the problem and validate the fix. – @Guido: Thank you (and have a good week while teaching SharePoint 😉 )!!!

 

Hints

As far as I have seen there are other solutions related to the same problem:

  • Check your user has at least Contribute rights on the site.
  • Check your site is in “Local Sites” or “Intranet” zone of the Internet Explorer.