We are working to upgrade a product that uses Crystal Reports for Visual Studio 2008 (10.5) to Visual Studio 2015 with service pack 15 (13.0). Everything seemed to be working fine until installing on a test server and crystal would hang on ReportDocument.Close(). I've tracked down the problem thanks to another post ReportDocument.Close() hangs indefinitely | SCN. The only difference between my development machine and the test server, is a CRUFL that is deployed to customers. If I unregister the crufl on the test server, the closing works fine. Is there a known difference in how crufls are handled between 10.5 and 13? Our crufl hasn't been modified in a few years and I believe its VB5.