I'm having a terrible problem on my SharePoint 2010 enterprise sites where all of the view pages that are using a customized XsltListView web part are throwing an error of "Unable to display this Web Part. To troubleshoot the problem, open this Web page in a Microsoft SharePoint Foundation-compatible HTML editor such as Microsoft SharePoint Designer. If the problem persists, contact your Web server administrator."
When I open the pages in SharePoint Designer everything appears to be normal, and I can even add a new Web Part on the page, select the specific list that was being used for the view and it will appear as normal (with the corrupted listview web part below it). Based on some searches, I already went down the path of changing the time limit for the XSL transformation from 1 second to 5 seconds, with no improvement. So now I'm down to the error message in the log file which appears as follows:
Web Parts 89a1 High Error while executing web part: System.NullReferenceException: Object reference not set to an instance of an object. at System.Xml.Xsl.XslCompiledTransform.Load(MethodInfo executeMethod, Byte queryData, Type earlyBoundTypes) at Microsoft.Xslt.STransform.GetCompiledTransform() at Microsoft.SharePoint.WebPartPages.BaseXsltListWebPart.LoadXslCompiledTransform(WSSXmlUrlResolver someXmlResolver) at Microsoft.SharePoint.WebPartPages.DataFormWebPart.GetXslCompiledTransform() at Microsoft.SharePoint.WebPartPages.DataFormWebPart.PrepareAndPerformTransform(Boolean bDeferExecuteTransform) 6e05010b-65ab-44d4-8a90-b92f7db9ac00
So it seems like SharePoint has lost it's reference to the specific XsltListView web part that we are using in the hundreds of page locations on about 30 different sites (this is also the reason I don't want to go and replace the List View web parts on every page where it currently exists). Is there any way to fix this object reference? Or is there some other problem that I'm missing? Please help!