What OS are you using. Is your OS fully patched? What USB to MIDI interface are you using? Are you using the latest driver for it. Are you using a USB port directly on your PC and not a USB hub. If using Windows 10, have you tried different MIDI modes (MINE and UWP)?
Also, on a MIDI project , select all and then use event list to make sure there are no stray events therein. Do your start notes and events start bang on 1:0:0 or do you have a "lead-in" measure before the events start. Does your project initialise patches for each track? - some MIDI hardware needs time to respond to these patches before sending other events. Do you have any initialisation strings set as sysex data.
