As of January 14th, 2020, SGPro is no longer supported on Windows 7. We will no longer be able to address any support issues coming from this OS. SGPro is still supported on Windows 8, Windows 8.1 and Windows 10 (and any other version of Windows that can use .Net 4.7.2). If you haven’t already, we highly recommend you upgrade to Windows 10. It is likely that you can still do this at no cost. See here: SGPro will no longer support Windows 7 - Upgrade for Free - Sequence Generator - Main Sequence Software