Symptoms
- Cursor doesn't move or keys don't register from the external device
- Device was working before and stopped suddenly
- Device works with another computer but not this Mac
- Wireless device's light doesn't turn on or blinks unusually
Likely causes
- CommonDead or low batteries in a wireless keyboard or mouseThis is the most common and simplest cause to check first.
- CommonA USB receiver not properly connected or in a problematic port/hubWireless dongles can be sensitive to their exact connection.
- CommonThe device not properly paired via BluetoothPairing can silently drop and need to be redone.
- PossibleA loose or faulty USB cable for a wired deviceCables are a frequent point of failure.
- PossibleA software setting affecting input recognitionAccessibility or input settings occasionally cause unexpected behavior.
What to do
- Replace or recharge the batteries in a wireless keyboard or mouse.
- For a USB receiver, try a different USB port directly on the Mac rather than through a hub.
- For Bluetooth devices, check System Settings > Bluetooth to confirm it's still listed as connected; if not, forget and re-pair it.
- For wired devices, try a different cable and port to rule those out.
- Test the device on another computer if possible to confirm whether the device itself is faulty.
- Restart the Mac, which can reset Bluetooth and USB connections.
- Check System Settings > Keyboard or Mouse/Trackpad for any unusual settings that might affect recognition.
- If a specific device never works on this Mac despite working elsewhere, and all connection troubleshooting is exhausted, a technician can check for a Bluetooth or USB hardware issue on the Mac.
Tools and parts
- Fresh batteries (for wireless devices)
- Known-good USB cable
When to call a pro
If a known-good external device still won't connect via any port or Bluetooth, an Apple-authorized shop can check for a hardware issue on the Mac's side.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.