Fix 1: Toggle Bluetooth off and on
Menu bar Bluetooth icon → turn off, wait 10 seconds, turn on. Surprisingly effective.
Solves 25% of cases — stuck Bluetooth service simply restarts.
Fix 2: Forget device and re-pair
System Settings → Bluetooth → 'i' next to device → Forget This Device → confirm. Then re-pair fresh.
Fixes saved-pairing-data corruption. Especially common after macOS updates.
Fix 3: Restart Mac
Apple menu → Restart. Bluetooth service rebuilds on boot. Often resolves Bluetooth detection issues that persist after toggle.
Fix 4: Reset Bluetooth module (Hidden Apple feature)
Hold Shift + Option, click menu bar Bluetooth icon → 'Reset the Bluetooth module' (older macOS) or use Terminal: sudo pkill bluetoothd.
More aggressive than toggle. Often fixes persistent issues.
Fix 5: Remove Bluetooth plist (advanced)
Finder → Go → Go to Folder → /Library/Preferences/. Delete: com.apple.Bluetooth.plist.
Restart Mac. Bluetooth rebuilds plist from scratch. Often clears configuration corruption.
Fix 6: Reset SMC + NVRAM (Intel only)
Intel: SMC reset (power off → Shift+Control+Option+Power 10 sec). NVRAM reset (power on holding Cmd+Option+P+R until 2 chimes).
Apple Silicon: just shutdown + restart.
Fix 7: Check for interference
Bluetooth shares 2.4GHz band with WiFi + microwaves + USB 3 cables.
Move USB 3 hard drives away from Mac (known interference source).
Try in different room. If works elsewhere = environmental interference.
Fix 8: Boot in Safe Mode
Apple Silicon: hold power → Continue in Safe Mode. Intel: hold Shift during boot.
If Bluetooth works in Safe Mode = third-party software interfering. Common: keyboard/mouse customisation tools, sleep-mode software.
When it's hardware
All software fixes fail + Bluetooth shows 'Not Available' in System Information.
Cause: WiFi/BT combo chip on logic board failed. Same chip handles both — failure often affects both simultaneously.
Fix: WiFi/BT chip rework PKR 35k–55k (board-level). Sometimes uneconomic — consider trade-in.