Mac screen recording not capturing audio

You can record internal audio on your Mac, but your Mac cannot natively record its own sound output, it can only capture sound from the internal or an agttached microphone during screen recording.

To capture the Mac's audio output, you need a virtual audio driver (for example, the free BlackHole) to route the sound into your screen recorder.

Step 1: Install a Virtual Audio Driver

• Download and install BlackHole 2ch (or another one, like LitLink)
• Restart your Mac if prompted during installation.

Step 2: Set Up Audio MIDI Devices

• Press Command + Space, type Audio MIDI Setup, and open the app.
• Click the + icon in the bottom-left corner and select Create Multi-Output Device.
• Check the boxes for BlackHole 2ch and your default MacBook Speakers (or headphones).
• Click the + icon again and select Create Aggregate Device.
• Check the box for BlackHole 2ch (and check your microphone if you also want to speak during the recording).

Step 3: Route Your Mac's Output

• Open System Settings and go to Sound.
• Click on Output and select your newly created Multi-Output Device.
• (Note: This sends sound to BlackHole for recording while still letting you hear it through your speakers).

Step 4: Record with QuickTime Player

• Press Command + Shift + 5 to open the built-in screenshot and recording toolbar.
• Click Options.
• Under the Microphone section, select BlackHole 2ch (or your Aggregate Device if using a mic too).
• Start your screen recording.
• When finished, remember to return to System Settings > Sound > Output and change your output back to your default speakers

More info:

Change the sound input settings on Mac – Apple Support

Set up MIDI devices using Audio MIDI Setup on Mac – Apple Support

On your Mac mini running macOS 26.2, press Shift-Command-5 to open Screenshot. 

Click Options and, under Microphone, select the microphone you want to use before starting the recording. 

Apple documents this option for recording your voice or other audio captured through a microphone. (Apple Support)

If no microphone audio is recorded, check that the microphone is selected in System Settings > Sound > Input and that the microphone is receiving sound. 

You can also review microphone access in System Settings > Privacy & Security > Microphone. (Apple Support)

If you want to record the audio being played by your Mac, Apple's documentation for Screenshot describes selecting a microphone and does not describe a separate system-audio option in Screenshot.

However, macOS allows supported apps and websites to record screen and system audio when permission is granted. 

These permissions can be reviewed in System Settings > Privacy & Security > Screen & System Audio Recording. (Apple Support)

For an additional and potentially more effective solution, consider installing third-party software. 

Refer to posting by @jeffereythefrog   this is the method I use: