Error when trying to edit Content Query Web Part in SharePoint 2013

Question

I have a CQWP on my publishing site welcome page. When I go to edit the web part, I get a "Sorry, something went wrong. An unexpected error has occurred." screen along with Correlation ID: c6e03d9c-f1be-f0a0-ed33-e826db494520. Does anyone know what is causing this? I've searched all over and can't find a solution.

Edit: I know think I found the error: "UserAgent not available, file operations may not be optimized." I still don't really know what that means or what to do.

Here's a little over a minute of logs. Click "toggle text wrapping" to make it readable. pastebin.com/jP0HAwy6 — Donald
And with the correct correlation id (different then the on in my OP) I get pastebin.com/936BFbEb Still new to SP, learning how to do all this. Posting these comments here in hopes that it will help somebody else at some point — Donald
I believe I found the error, "UserAgent not available, file operations may not be optimized." Not entirely sure what that means — Donald

msounthar msounthar · Accepted Answer · 2013-08-30T07:22:50

Going through your logs, the error you are getting is

   System.ArgumentNullException: Key cannot be null.  Parameter name: key   
 at System.Collections.SortedList.IndexOfKey(Object key)    
 at System.Collections.SortedList.ContainsKey(Object key)    
 at Microsoft.SharePoint.Publishing.WebControls.ContentByQueryToolPart.AppendListTypes(SortedList sortedListItems, SPListTemplateCollection listTypes)    
 at Microsoft.SharePoint.Publishing.WebControls.ContentByQueryToolPart.populateListTypeDropDown()    
 at Microsoft.SharePoint.Publishing.WebControls.ContentByQueryToolPart.populateCBQControls()    
 at Microsoft.SharePoint.Publishing.WebControls.ContentByQueryToolPart.OnPreRender(EventArgs e)    
 at System.Web.UI.Control.PreRenderRecursiveInternal()    
 at System.Web.UI.Control.PreRenderRecursiveInternal()    
 at System.Web.UI.Control.PreRenderRecursiveInternal()    
 at System.Web.UI.Control.PreRenderRecursiveInternal()    
 at System.Web.UI.Control.PreRenderRecursiveInternal()    
 at System.Web.UI.Control.PreRenderRecursiveInternal()    
 at System.Web.UI.Control.PreRenderRecursiveInternal()    
 at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

Ensure that "Title" column for all items in that list are not null. This is the mostly likely cause for this issue.

Error when trying to edit Content Query Web Part in SharePoint 2013

3 Answers