Your USB-C hub is connected to your Mac, but suddenly macOS displays a warning such as:
- “USB Accessories Disabled”
- “USB Devices Disabled”
- “Unplug the accessory using too much power”
- “The device needs more power”
- “The operation can’t be completed”
Your external SSD, hard drive, camera, card reader, keyboard, or other USB device may disappear at the same time. Meanwhile, HDMI may continue working, and your Mac may still appear to charge.
This usually means that one or more connected accessories are requesting more power than the current USB connection can safely provide. It does not automatically mean your Mac, hub, or external device is broken.
Quick Answer
When a Mac says USB accessories or USB devices are disabled, disconnect the affected devices, connect the hub directly to another Mac port, and test the accessories one at a time.
If the hub supports Power Delivery, connect a suitable charger to its PD port before reconnecting high-power devices such as external hard drives, cameras, webcams, or phones.
Apple’s official USB Devices Disabled guide also recommends testing another Mac port, connecting the device directly, and confirming that a self-powered hub is connected to its AC adapter.
Read the Warning as a Power-Budget Problem
A Mac USB-C port can provide power to connected accessories, but that power is limited.
Your hub also needs power to operate its internal controller, HDMI output, Ethernet, card reader, and USB ports. Every bus-powered device connected to the hub then uses part of the remaining power.
Think of the connection as a shared power budget:
| Connected Device | Typical Power Demand |
|---|---|
| Wired mouse or keyboard | Low |
| USB receiver | Low |
| SD or microSD card reader | Low to moderate |
| USB flash drive | Low to moderate |
| Webcam | Moderate |
| Phone | Moderate to high |
| Portable SSD | Moderate to high |
| Portable hard drive | High during startup |
| Camera connected for tethering | Moderate to high |
| Several devices together | Combined demand may exceed the available power |
A single keyboard may work normally. However, adding an external hard drive, webcam, phone, and card reader can push the setup beyond the available power.
When that happens, macOS may disable one or more USB devices to protect the Mac and connected hardware.
Which Situation Matches Your Mac?
The warning appears as soon as the hub is connected
The problem may involve:
- The hub cable
- The Mac USB-C port
- A damaged connector
- An unsupported adapter chain
- A fault inside the hub
- A device already connected to the hub
Disconnect everything from the hub and test the hub by itself.
The warning appears only after connecting an SSD, hard drive, or camera
The newly connected device is probably requesting more power than the hub can currently provide.
Connect your Mac charger to the hub’s PD port, or test the device directly on the Mac.
The device charges but does not transfer data
This may be a permission problem rather than a power problem.
Mac laptops with Apple silicon can ask you to approve new USB, Thunderbolt, or SD card accessories. Apple notes that an accessory may still charge even when data access is not allowed.
Check Apple’s Allow USB and other accessories to connect to your Mac guide if the device receives power but is not recognized.
Use This Safe Power Reset
Before changing drivers, replacing cables, or buying another hub, reset the connection in a controlled order.
1. Stop active file transfers
Do not immediately unplug an external drive while files are being copied.
Pause the transfer and eject the drive safely through Finder if it is still visible.
2. Disconnect the hub from the Mac
Remove the hub and wait approximately 10 seconds.
3. Remove every accessory from the hub
Disconnect:
- SSDs and hard drives
- Cameras
- Phones
- Webcams
- USB drives
- Card readers
- Keyboards and mice
- HDMI and Ethernet if necessary
4. Unlock the Mac
On an Apple silicon MacBook, keeping the Mac unlocked also makes it easier to approve a new accessory connection.
5. Connect the charger to the hub first
If the hub supports Power Delivery, connect a suitable charger to the PD input before connecting the hub to the Mac.
Do not plug a storage device into the PD port. The PD port is normally intended for charging input, not USB data.
6. Connect the hub directly to the Mac
Avoid USB-C extension cables, extra adapters, monitor USB ports, or another hub during testing.
7. Add accessories one at a time
Use this order:
- Keyboard or mouse
- USB receiver
- USB flash drive
- Card reader
- Webcam
- Portable SSD
- Portable hard drive
- Camera or phone
Wait several seconds after adding each device.
When the warning returns, the most recently connected accessory—or the total combined load—is the likely trigger.
Why HDMI May Still Work While USB Devices Are Disabled
This situation often causes confusion.
Your external monitor may continue displaying an image while an SSD, webcam, or camera disappears. That can happen because video output and USB accessory power are different parts of the connection.
An HDMI monitor normally has its own power supply. The hub mainly carries the video signal to the monitor.
A portable hard drive, phone, webcam, or camera may draw operating power directly through the USB connection. These devices place a greater demand on the Mac and hub’s available power.
Therefore:
- HDMI working does not prove that every USB port has enough power.
- Mac charging does not prove that all accessories are receiving enough power.
- A device lighting up does not prove that it has a stable data connection.
Check the Charger, Cable, and Complete PD Chain
A hub labeled “100W PD” does not create 100W of power. It passes power from the charger through the hub to the Mac and connected devices.
The actual result depends on the entire chain:
Charger → USB-C charging cable → Hub PD port → Hub → Mac and accessories
Check these points:
Charger wattage
A small phone charger may not provide enough power for a MacBook, hub, and multiple external devices.
Use a charger appropriate for your Mac model and workload.
Charging cable capability
The cable between the charger and hub must support the required Power Delivery level.
A low-power or damaged cable can limit charging even when the charger and hub support higher wattage.
Hub power consumption
The hub uses part of the incoming power for its own controller and ports. The full charger wattage will not necessarily reach the Mac.
Mac charging limit
The Mac only accepts the charging level it supports and currently needs.
Connected accessories
External storage, cameras, webcams, phones, and other devices also use power from the system.
For a portable setup with HDMI, card readers, and basic USB devices, a USB-C hub with Power Delivery can provide a more stable power path when connected to a suitable charger.
Test High-Power Devices Directly
If one device repeatedly triggers the warning, connect it directly to the Mac.
If the device works directly
The device is probably functional. The hub setup may not have enough available power, or too many accessories may be connected simultaneously.
If the device still fails directly
Test:
- Another Mac port
- Another USB cable
- Another computer
- The device’s own power adapter, if supported
- A different enclosure or storage device
The problem may be the accessory, cable, enclosure, or Mac port rather than the hub.
If the device works only when separately powered
The device likely needs more power than the bus-powered setup can provide.
A powered USB-C hub for Mac or a docking station connected to an appropriate charger may be more suitable.
Check Mac Accessory Permissions
Do not confuse a power warning with a permission warning.
On Mac laptops with Apple silicon, go to:
Apple menu → System Settings → Privacy & Security → Accessories
Depending on your macOS version, you may see options such as:
- Always ask
- Ask for new accessories
- Automatically allow when unlocked
- Always allow
If you previously selected “Don’t Allow,” reconnect the device while the Mac is unlocked and approve the connection.
Apple explains that denied accessories can still charge while remaining unable to access Mac data. This is why “the device is charging” does not always mean “the device has been recognized.”
Remove Adapter Stacking
Avoid connection chains such as:
Mac → USB-C extension → Hub → Another hub → External drive
Or:
Mac → Monitor USB-C port → Hub → Camera
Each additional adapter, cable, or hub can introduce:
- Power loss
- Unstable negotiation
- Data limitations
- Loose connections
- Unsupported port functions
During troubleshooting, use the simplest path:
Mac → USB-C hub → Accessory
If the simple path works, rebuild the setup one connection at a time.
When a Docking Station Makes More Sense
A compact portable hub is suitable for everyday accessories. However, a fixed workstation may include:
- External monitor
- Ethernet
- Webcam
- USB microphone
- Keyboard and mouse
- Portable SSD
- Phone
- Speakers
- Card reader
- Laptop charging
In this situation, a USB-C docking station for multiple devices may be easier to manage than stacking several portable adapters.
Look for:
- Clearly labeled PD input
- Enough USB data ports
- A separate host connection
- A suitable charger
- Clear compatibility information
- A stable desktop cable layout
Even with a docking station, you should still connect the charger before several high-power accessories when the manufacturer recommends that order.
Protect Your Files After a Power Warning
A sudden loss of power can interrupt an active storage operation.
After seeing the warning:
- Stop copying or editing files on the affected drive.
- Check whether the drive remains visible in Finder.
- Eject the drive before disconnecting it.
- Reconnect it directly if the hub connection is unstable.
- Confirm that recently transferred files open correctly.
- Run Disk Utility First Aid if the drive behaves abnormally.
- Avoid repeatedly reconnecting the drive during an active write operation.
For important files, keep a second backup rather than relying on one external drive.
Choosing the Right Setup
Light portable use
For a keyboard, mouse, flash drive, card reader, and occasional HDMI output, choose a USB-C hub with Power Delivery.
Multiple USB-C storage devices
For several USB-C SSDs, phones, or modern data accessories, choose a hub with clearly labeled USB-C data ports and PD input.
Remember that USB-C data ports may not support video output or independent device charging unless the product explicitly says so.
Fixed Mac workstation
For a monitor, Ethernet, audio, storage, webcam, keyboard, mouse, and charging, choose a USB-C docking station for multiple devices.
Power-hungry equipment
For portable hard drives, cameras, capture devices, or multiple external devices, prioritize a powered USB-C hub for Mac and a suitable charger.
FAQ
What does “USB Devices Disabled” mean on Mac?
It usually means that one or more connected USB devices are requesting more power than the current connection can provide safely.
Is my USB-C hub broken?
Not necessarily. The warning may be caused by a high-power accessory, weak charger, limited cable, overloaded hub, adapter chain, or temporary connection problem.
Why does the warning appear when I connect an external hard drive?
Portable hard drives can require more power during startup. Connect the Mac charger to the hub’s PD port, remove other devices, or test the drive directly.
Why does HDMI work while my USB drive is disabled?
The monitor normally has its own power supply, while the USB drive may depend on power from the Mac or hub. Video and USB accessory power can behave differently.
Should I connect the charger or accessories first?
For a PD hub handling several high-power devices, connect the charger to the hub first, then connect the hub to the Mac and add accessories one at a time.
Can accessory permissions cause a similar problem?
Yes. On Apple silicon Mac laptops, a denied accessory may still charge but remain unavailable for data. Check Privacy & Security settings if the device has power but is not recognized.
Final Thoughts
When your Mac says USB accessories or USB devices are disabled, begin with power—not software.
Disconnect the hub, remove all accessories, connect a suitable charger to the PD port, reconnect the hub directly, and add devices one at a time. This will usually reveal whether the problem is one high-power device, the combined load, the charging chain, or the accessory permission setting.
For light portable use, a USB-C hub with Power Delivery may be enough. For external drives, cameras, webcams, and several accessories, a powered USB-C hub for Mac or USB-C docking station for multiple devices can provide a more practical and stable connection.
