I understand that you're experiencing an issue with your Mac Mini where the sound stops going to the headphone jack and instead comes from the internal speakers. I'd be happy to help you troubleshoot this problem.
Here are a few suggestions you can try:
1. Check the connection: Ensure that the headphone jack is securely plugged into the Mac Mini. Sometimes a loose connection can cause audio issues. You can try gently wiggling the jack to see if the sound intermittently switches between the headphone and internal speakers.
2. Verify sound settings: Open "System Preferences" from the Apple menu and select "Sound." Make sure that the output device is set to "Headphones" or "External Speakers" rather than the internal speakers. If it's already set correctly, try changing it to the internal speakers, then back to the headphones or external speakers to see if it resolves the issue.
3. Restart the Mac Mini: Sometimes, a simple restart can fix various software-related problems. Go to the Apple menu and choose "Restart" to reboot your Mac Mini. After it restarts, check if the sound is consistently routed to the headphones.
4. Reset NVRAM/PRAM: Resetting the non-volatile random-access memory (NVRAM) or parameter random-access memory (PRAM) can help resolve certain audio-related issues. Shut down your Mac Mini, then turn it back on and immediately press and hold the Command + Option + P + R keys on your keyboard. Keep holding them until you hear the startup chime for the second time, then release the keys. Your Mac Mini will restart, and you can check if the sound behaves as expected.
5. Test with different headphones/speakers: If possible, try using different headphones or speakers to rule out the possibility of a hardware problem with the current set of external speakers you're using.
If none of the above steps resolve the issue, it's worth considering updating your Mac Mini's software to the latest version. You can check for available updates by going to the Apple menu, selecting "System Preferences," and clicking on "Software Update."
If the problem persists, you may want to consider contacting Apple Support or visiting an Apple Store for further assistance, as they can provide specialized guidance based on your specific Mac Mini model and software version.
I hope these suggestions help you resolve the sound issue with your Mac Mini. If you have any further questions or need additional assistance, feel free to ask.