“USB Accessories Disabled” or “USB Devices Disabled”, sometimes followed by “Unplug the accessory using too much power to re-enable USB devices,” means a connected device needs more power than the Mac can provide through its current connection path. This applies to USB-A, USB-C and Thunderbolt accessories on Apple silicon and Intel Macs. The safest first action is to disconnect and reconnect the affected accessory, but do not unplug mounted storage while it is reading, writing or transferring files.
What “USB Accessories Disabled” means
According to Apple’s USB Devices Disabled guidance, this warning identifies a power shortage between the Mac and the connected device. The accessory might be connected directly, or its available power might be limited by a hub, dock or other shared connection path.
The closely equivalent messages “The device needs more power” and “The operation can’t be completed because the connected device needs more power” indicate the same power-related context covered here. The warning alone does not prove that the accessory, cable, port, hub or Mac hardware has failed.
Apple does not provide different warning-specific fixes for Apple silicon and Intel Macs in the cited support article. The same connection and power checks below therefore apply to both architectures.
This guide does not cover accessory-approval prompts, security permission dialogs, “Accessory Not Supported,” or general device-detection problems without the power warning. If the displayed message instead concerns software update personalization errors, use the separate update-resolution guide.
Before disconnecting an external drive
Do not unplug a mounted external drive while files are being read, written or transferred. Unexpected disconnection can interrupt the active operation. Apple’s approved warning-specific article does not provide a storage-safe ejection procedure, and no verified ejection UI path was supplied for this article.
If the affected accessory is mounted storage and you cannot confirm that it is safe to disconnect, stop before performing any step that requires unplugging it. Do not force-eject, erase, reformat or repair the drive to address this power warning. The message does not establish that the drive is corrupted.
Follow Apple’s confirmed USB power checks in order
These are the warning-specific connection and power checks documented by Apple. Each check is low risk when the accessory can be safely disconnected, but none is guaranteed to clear the warning.
1. Reconnect the accessory
When it applies: Use this first for the exact USB power warning family.
Prerequisite: You need safe access to the accessory and Mac port. If the accessory is mounted or active storage, follow the safety limitation above before disconnecting it.
- Disconnect the external device from the Mac.
- Reconnect it to the Mac.
Expected result: The Mac may re-enable the device if reconnecting establishes a usable power path. If the warning remains, continue to the next check.
Risk and rollback: Risk is low. No rollback is needed.
2. Try a different Mac port
When it applies: Use this if reconnecting does not restore the device.
Prerequisite: Another compatible port must be available on the Mac.
- Disconnect the accessory.
- Connect it to a different port on the Mac.
Expected result: The accessory may work through the alternate connection path. This comparison does not by itself prove that the original port is defective.
Risk and rollback: Risk is low. Move the accessory back to the original port if needed.
3. Bypass the hub or dock
When it applies: Use this if the accessory is connected through a USB or Thunderbolt hub or dock.
Prerequisite: A compatible direct connection to the Mac must be possible.
- Disconnect the accessory from the hub or dock.
- Connect the accessory directly to the Mac.
Expected result: A direct connection may provide a sufficient power path or show that the warning is associated with the shared connection. One successful test does not establish that the hub or dock is defective.
Risk and rollback: Risk is low. Reconnect through the hub or dock if a direct connection is no longer needed.
4. Supply AC power to a self-powered hub or dock
When it applies: Use this when the accessory must remain connected through a hub or dock that supports external power.
Prerequisites: The hub or dock must support AC power, and its AC adapter must be available.
- Disconnect the hub or dock if needed.
- Connect the hub or dock to its AC adapter.
- Reconnect the accessory through the powered hub or dock.
Expected result: The externally powered equipment may provide enough power for the attached accessory without relying only on the Mac connection.
Risk and rollback: Risk is low. If necessary, return to the prior setup by disconnecting the equipment safely and removing AC power.
5. Check the accessory’s documented power and cable requirements
When it applies: Use this when the accessory has its own power source or requires a particular cable or adapter.
Prerequisite: The accessory manual or manufacturer support page must be available.
- Review the accessory documentation.
- Confirm whether the accessory needs an additional power source.
- Use the correct cable or adapter documented for that accessory.
Expected result: Meeting the manufacturer’s documented power and connection requirements may remove the power bottleneck. Apple’s iMac accessory guidance advises checking whether equipment requires an additional power source, while Apple’s MacBook Pro accessory guidance also addresses using the appropriate cable or adapter.
Risk and rollback: Risk is low. Restore the prior cable or power setup if needed.
Avoid unsupported or destructive fixes: Apple’s warning-specific sequence does not confirm restarting as the primary fix, resetting the SMC or NVRAM, running Terminal commands, using maintenance utilities or reinstalling macOS. Do not erase or reformat attached storage, and do not change accessory-approval or security settings for this power warning.
How to isolate the accessory or shared connection path
If several accessories share a hub or dock, one-device-at-a-time testing can help compare connection paths after all mounted-storage safety concerns have been addressed. This is a cautious diagnostic method, not a procedure published in Apple’s warning-specific article.
- Test one accessory at a time rather than reconnecting the entire shared chain at once.
- Compare the result when the accessory is connected directly to the Mac and when it is connected through the hub or dock.
- If the warning follows one documented cable or accessory configuration, review the relevant manufacturer instructions for power, cable and adapter requirements.
- Do not declare a cable, port, accessory, hub or dock defective based on one test.
Hubs, docks and shared bus-powered chains are common contexts for this warning, but they are not the only possible context. System Information is not included as a required diagnostic step because the approved Apple material does not document a consistent System Information workflow for this exact warning.
When to contact Apple Support
Apple directs users to contact Apple Support when the documented connection and power checks do not resolve the issue. Record the exact warning wording and which confirmed paths you tested so that the unresolved behavior can be described accurately.
A warning that continues when no accessories are attached, appears with every tested port or coincides with USB-C charging failure is a reason to stop repeating accessory reconnection attempts and seek assessment. These are cautious escalation signals based on limited evidence, not proof that a port, charger or internal Mac component has failed.
Do not disassemble the Mac, reinstall macOS or perform unsupported resets as a prerequisite for escalation. The evidence supplied for this guide supports connection-path testing and Apple Support escalation, not a specific hardware-failure diagnosis.