How do I fix intermittent sound issues on MacBook Air (early 2015) running macOS Monterey?

"Somehow after all the work I have done, the problem still persists. I will probably have to get a new Mac"

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Transferring to a New Mac:

Being a decade olde, you no longer can receive security updates for the macOS. I agree that it is time to upgrade. So, rather than spending a boatload on apps, or going through a great hassle of data transfer, you can migrate items easily through use of Migration Assistant. Some apps, you would need a new license key, and they will not transfer, due to piracy concerns and incompatibly issues of the Developer.. So, contact the Developer, asking them if you can have a replacement license key for this new Mac.

Using Time Machine Backup (TMB)

1. Create a TMBof this Mac...

Create a Time Machine Backup of this 2015 Mac, that way you can have something to restore your Mac from, should you need items back, and to migrate it all back.

then...

2. Use Migration Assistant to Transfer:

Connect the 2015 Ma's TMB to the new Mac, and then transfer data.

1. Go Here: How to move your content to a new Mac - Apple Support
2. Scroll to: Use Migration Assistant
3. Proceed from there as necessary

"How do I fix intermittent sound issues on MacBook Air (early 2015) running macOS Monterey?: I have a Macbook Air(early 2015) running macOS Monterey. I have issues where the sound does not work and it is intermittent. My research shows that I must delete the 2 .plist files com.apple.audio.DeviceSettings.plist and com.apple.audio.SystemSettings.plist. However, it is a hit or miss.Is there any other solution to this problem?"

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Fixing your Audio:

Reinstall the macOS:

To get these files replaced or replaced, perform a reinstall of the macOS. Nothing would be deleted; damaged items would be replaced, and missing items would be relocated to where the should be. Go Here: How to Reinstall macOS from macOS Recovery - Apple Support. Important: Be certain to create a backup of your Mac prior to all of this. That way, you can have something to restore from the Mac from, should anything go wrong with the reinstall. Once reinstalled, try this once more.

"Unfortunately, I am running into a different error when I get to Recovery Mode. com.apple.buildinfo.preflight.error 21"

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Thank you for the followup reply.

Reinstalling the macOS on an Intel-based Mac:

Overview what is provided here, and how to perform this: Use macOS Recovery on an Intel-based Mac - Apple Support

Internet Recovery Mode:

"com.apple.buildinfo.preflight.error 21" indicates there is an error connecting to Apple's servers. So, Internet Recovery Mode is what you might be performing here. So, power off your Mac, and then, when you hear the boot come, hold down Option (⌥) + Command (⌘) + R until you see a globe spinning.

A. Have an Internet Connection:

You need an Internet connection to perform this. You can do so wired or wirelessly. Go here: Connect to the internet using Wi-Fi. Look for the network connection icon located not he top-right corner of Recovery Mode.

B. Restart the Mac.

Power off you Mac, and then try this once more.

C. Use Frist Aid:

While in Recovery Mode, select the drive and then click First Aid button. Do the same for all partitions.

D. Reset the SMC and your NVRAM:

(Applies to Intel-Based Macs Only): Sometimes when changes are made to the system(i.e. Ports), system configurations (i.e. for Power) become manipulated, technically. So, reset the SMC and NVRAM. Try performing each thrice. It may take sometime, being certain you have the time to perform these resets.

E. Reinstall macOS in Internet Recovery Mode:

On your Intel-based Mac, you a performer a reinstall the macOS using Internet Recovery Mode. Go here: Use macOS Recovery on an Intel-based Mac - Apple Support

"I finally was able to re-install, MacOS Monterey. I had to install Yosemete then update the Mac to Monteray. I got help from an Apple Representative and was shown how to get the latest build designed for your mac. After powering down by holding the power button for at least 10 seconds, hold the Option + Command + R buttons. This should work."

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Great work!

Back Up your Mac:

Important: Be certain to create a backup of your Mac having performed this update. That way, you can have something to restore from the Mac from, should anything go wrong from here on out.