Version 3.12 of DiffEngineX was released on 21st November 2016. This version fixes problems with Excel exceptions and errors being intermittently thrown during and after the process of comparing two Excel workbooks. The root cause is due to Microsoft updates to their Windows and Office software.
If you are running 3.04 or earlier, it is not possible to automatically update to version 3.12. Please manually uninstall using the Windows Control Panel->Programs functionality, before installing the new version from here.