Following an upgrade from SharePoint 2010 to 2013 I deployed some custom web parts. When loading the page I received the error “/_CONTROLTEMPLATES/WEBPARTNAME/VisualWebPart1/VisualWebPart1UserControl.ascx” does not exist.
The error is caused by the web part looking in the \14\TEMPLATE\CONTROLTEMPLATES folder rather than \15\TEMPLATE\CONTROLTEMPLATES. Open the web part solution in Visual Studio and change the _ascxPath string. Original value below:
Change the string to include the 15 folder.
Rebuild and re-deploy the web part.