Sonos gives the Ace a standard reboot, a force reboot and a factory reset. Standard reboot: disconnect USB-C, press and hold the Power/Bluetooth button on the left earcup for about 3 seconds until the power-off tone and the light turns off, wait 10 seconds, then hold about 3 seconds to power on. Force reboot: hold the power button for roughly 15 seconds; the button article says a 10-second hold with USB-C disconnected performs a forced reboot. Factory reset needs a powered USB-C cable:
connect the cable to a power source but not to the headphones, make sure the headphones are on, hold the power button and immediately plug the cable into the left ear cup, keep holding until the status light flashes white (up to 10 seconds), then unplug and release. The headphones enter pairing mode with a flashing blue light. Before reconnecting to a previously used device, forget the Ace in that device's Bluetooth or Connected Device settings. A reset removes registration and pairings, is used before selling, and should not be the first troubleshooting step.
Differential
Likely causes of “Sonos Ace headphones needs a safe reset or will not reset”, and how to tell them apart
- 1
A frozen headset
What separates it There is no response to buttons because the headset has frozen
How to confirm Force a reboot, by holding the button, and check whether they respond
- 2
A failed setup
What separates it The app cannot register the headphones because the setup failed
How to confirm Factory reset the headphones, and then set them up again in the app
- 3
You are selling it
What separates it The buyer needs a clean set because you are selling the headphones
How to confirm Factory reset the headphones, so the buyer gets a clean set
- 4
A stale pairing
What separates it The headphones will not reconnect because of a stale pairing
How to confirm Forget the headphones on your device first, and then pair them again
- 5
A stuck update
What separates it The light is stuck because an update is stuck
How to confirm Force a reboot, and then retry the update from the start
Before you touch a setting
Record this first — changing settings destroys the evidence
- The model of the headphones that you have
- The reason why you are resetting them
- What the status light does at the moment
- Whether you have a powered USB-C cable ready
Try in this order
0 of 7 completedReboot first
ReversibleReboot first, by holding power for about three seconds, waiting ten seconds, and powering on.
Force reboot
ReversibleForce a reboot, by holding power for about fifteen seconds, with USB-C disconnected, and then test again to see whether it helped.
Prepare a powered cable
ReversiblePrepare a powered cable, by connecting a USB-C cable to a power source but not to the headphones.
Start the reset
ReversibleWith the Ace on, hold power and plug the cable into the left ear cup.
Wait for white
ReversibleWait for white, holding the button until the light flashes white, which takes up to ten seconds.
Unplug and release
ReversibleUnplug the cable and release the button, and then the light flashes blue for pairing.
Forget on your device
ReversibleForget on your device, by removing the Ace from the remembered connections before you re pair.
Model-specific
What is true of this model and not of its siblings
- Reset
- Sonos: the Sonos Ace and Ace Ultra need a powered USB-C connection during part of the reset.
- Reboot
- Standard reboot is a 3-second hold with USB-C disconnected; force reboot is a hold of roughly 10 to 15 seconds.
Stop boundary
When this stops being a self-service repair
- !If the light never flashes white during a reset, contact Sonos Support
- !If it will not power on at all, contact Sonos
- !If you sold the headphones, confirm the reset before you hand them over
Evidence ledger
Sources behind this answer
The Ace reset with a powered USB-C cable.
Standard and force reboot for the Ace.
The 10-second forced reboot.
Forgetting the headphones after a reset.
The company and its products.
Exact questions
Common questions
How do I factory reset the Ace?+
Hold power while plugging a powered USB-C cable into the left ear cup until the light flashes white.
How do I reboot it?+
Hold power about 3 seconds, wait 10, hold again to power on.
What is a force reboot?+
A 10 to 15 second hold if the headphones are frozen.
Does a reset delete pairings?+
Yes; forget the Ace on your device before reconnecting.
What does the light do after a reset?+
After a reset, the light flashes blue, which shows that it is ready for pairing.
Do I need the app after a reset?+
Yes, to register and update again.
Should I reset to fix problems?+
Try a reboot first, since a reset erases your settings and rarely fixes a fault.
Does the Ace Ultra reset the same way?+
Yes, the Ace Ultra resets the same way, according to Sonos's article.
What if it stays on white?+
If it stays on white, repeat the steps carefully, holding the button for the full time.