Some of the issues in a Pre-Upgrade Check Report are straight forward to fix, but what do you do about this one? “Issue : Missing server file or server configuration issues”
In a site collection with thousands of sites, it is not an option to manually track down these obsolete webparts. So I wrote a SQL statement to identify the sites/pages. This statement is for the webpart with the Id ‘34febc2f-1526-47d8-d72a-7b992ac65a7d’.
FROM [WSS_Content].[dbo].[AllDocs] INNER JOIN [WSS_Content].[dbo].[WebParts]
ON [AllDocs].Id = [WebParts].[tp_PageUrlID]
WHERE [WebParts].[tp_WebPartTypeId] = '34febc2f-1526-47d8-d72a-7b992ac65a7d'
Now you have a nice list of the pages where you need to remove the webpart.
Go to the Web Part Page Maintenance (<url>?contents=1) and delete the webpart.