Hi there! I see you’re having a crash issue with MIDI files in n-Track Studio on your Mac running OS X 10.15. Can you tell me a bit more about the crash? For example:

- Does the crash happen when opening a specific MIDI file, or when editing, playing, or importing it?
- Is the crash immediate or does it occur after some action (like dragging a clip, or syncing to MIDI clock)?
- Have you noticed if the crash happens with all MIDI files or just one?
- Also, are you running the latest version of n-Track Studio compatible with your OS?

These details will help me narrow down the cause.

Meanwhile, here are some general steps to troubleshoot MIDI-related crashes in n-Track on your Mac:

1. Check MIDI Device Setup and Preferences:
Go to File > Preferences > MIDI Settings, and verify that the MIDI devices and VST instruments outputs are correctly selected. Sometimes misconfigured MIDI outputs can cause instability.

2. Try with a Simpler MIDI File:
Open or import a simple, short MIDI file to see if the crash occurs. Complex or corrupted MIDI data can cause crashes when the software tries to interpret it.

3. Disable MIDI Sync or Clock Slave Mode:
Some forum users reported crashes when syncing to MIDI clock input. Try turning off any MIDI clock sync or slaving options temporarily and see if the crash persists1.

4. Update or Reinstall n-Track Studio:
Ensure you have the latest stable version for macOS 10.15. If you already do, try reinstalling to fix potential corrupted files.

5. Check Plugins and VST Instruments:
Sometimes third-party plugins or VSTi instruments linked to MIDI tracks can cause crashes. Try removing or bypassing them on the MIDI track.

6. Test on a New Project:
Create a new project and insert a MIDI track. Import the file or record something briefly to confirm whether the crash is project-specific.

If the issue continues after this, let me know what you’ve tried and any crash messages or behaviors you see. We can then try some deeper troubleshooting or consider submitting a bug report.

Are you comfortable trying these steps? And please share any details you observe during the crash.