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K2 Management Site loads a blank page and SmartForms Runtime Site spins continuously


K2 Management Site loads a blank page and the SmartForms Runtime Site spins continuously

This article was created in response to a support issue logged with K2. The content may include typographical errors and may be revised at any time without notice. This article is not considered official documentation for K2 software and is provided "as is" with no warranties.


After upgrading to K2 Five, the K2 Management Site loads a blank page and Forms running via the 'Runtime/Runtime' URL spins continuously.



Forms do load when using the 'Designer/Runtime' site; this indicates a difference in configuration between the two sub-sites.


The following JavaScript error was also logged in the F12 Developer Tools:


Unable to get property 'setAntiXSRFHeader' of undefined or null reference


It was determined that the following key was implemented in a previous version of K2 which had resulted in this behavior:

<add key="Forms.LegacyBrowserSupport" value="true" />


To resolve the issue, comment out the "Forms.LegacyBrowserSupport" key in the web.config file for the Runtime site.

<!-- <add key="Forms.LegacyBrowserSupport" value="true" /> -->

This is usually at location (C:\Program Files (x86)\K2 blackpearl\K2 smartforms Runtime).

This is commented out by default settings and is only applicable for K2 versions 4.6.9 and 4.6.10.


K2 Five is not compatible with SharePoint 2010 and compatible with version 11 of Internet Explorer:

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Last update:
‎05-19-2021 02:42 PM
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