Connected Bluetooth Device Not Recognized as Audio Device Short Version:

The device in question is connected according to itself and the Bluetooth Preferences, but does not show up as an output option in Sound Preferences.

Long Version:

I recently purchased an AmazonBasics Bluetooth Audio Receiver with the intention of being able to broadcast from my phone, MacBook, etc. to a pair of non-Bluetooth speakers from across the room. Most of my computer problems are self-inflicted, so I'd imagine this has to do with some changes I made a few months back that I will detail further down.

The computer experiencing issues is a 2012 MacBook Pro 13" (MacBookPro9,2), running Yosemite 10.10.5.

Here's what I know:


The device connects and shows up as a connected Bluetooth device in System Preferences.
The device is not recognized as an audio device on my 2012 MacBook Pro (it doesn't show up in the preferences pane).
The device is able to receive audio from my Android phone.
The device is able to receive audio from my 2010 MacBook Pro running the same OS version (10.10.5), less a security update and various app updates.
I had to manually remove Avid ProTools components a few months ago, so likely the issue is with something I edited incorrectly.
Copying com.apple.audio.SystemSettings.plist from the 2010 model to the 2012 model does not correct the issue.
Deleting com.apple.audio.SystemSettings.plist from the 2012 model outright does not correct the issue.
Restarting, etc. does not correct the issue.


I suspect that there is some kext file or similar package that needs to be reset or replaced with a good one, but don't know where it would be.

I do not want to (nor should I have to, in theory) reinstall my system due to a million and a half other reasons.

I realize that this is an unusual issue, as various search engines with various terms yielded nothing fruitful. Any assistance you can offer is appreciated.

MacBook Pro (13-inch Mid 2012), OS X Yosemite (10.10.5)
Resolution:

I installed Yosemite on an external drive so that I could find all the system files related to audio (using EasyFind, a great search utility for Mac), compare them to my existing system for any file size mismatches, and then replace the offending file(s).

The offending file was found in /Library/Audio/Plug-Ins/HAL and was most likely "BluetoothAudioPlugin.driver" (duh), though I replaced all the files in this folder with the system defaults, so I don't know that it was solely caused by this one alone.