Introduction After upgrading a collaboration site from SharePoint 2010 to SharePoint 2013, an error was received when using the People Picker in SharePoint. A "JSON is undefined" error is received when initiating the People Picker. Solution Douglas Crockford has provided the json2.js script on GitHub. Make a copy of this script and paste it into the LAYOUTS directory in SharePoint 2013. Typically, you create a directory scripts before and paste json2.js into that directory. Locate the file pickerdialog.master in the LAYOUTS directory and make a copy of this file for backup. Open the file pickerdialog.master and find the following line <sharepoint:scriptlink language="javascript" name="core.js" localizable="false" runat="server" /> Above this line, create this entry <sharepoint:scriptlink language="javascript" name="/_layouts/15/Scripts/json2.js" localizable="false" runat="server...