Philips Hue 'Software Update Failed' — How to Fix It

What it means

A Hue update can fail for the Bridge itself or for individual bulbs and accessories.
For the Bridge it's usually an internet hiccup or the Bridge's connection dropping mid-download; for bulbs it's a bulb that lost power or was out of Zigbee range while the update was being pushed.
It rarely breaks anything — the safe move is to make sure everything has steady power and a solid connection, then run the update again.

Affected Models

Hue Bridge v2 (square) software updates
Philips Hue bulbs of all types (firmware pushed via the Bridge)
Hue dimmer switches, Tap dial, motion sensors and smart plugs
Hue Bridge v1 (round) — discontinued, no longer receiving updates

Common Causes

Internet dropped or was slow during the Bridge download
Bridge's Ethernet link or router glitched mid-update
A bulb lost power (wall switch off) while its firmware was being updated
A bulb was out of Zigbee range or the mesh was unstable during the push
Bridge needs a reboot to retry cleanly
Too many devices updating at once over a weak mesh
Trying to update an old v1 Bridge, which no longer gets updates

How to Fix It

Check everything has power and a connection.

Make sure the Bridge's three lights are on, your internet is working, and all the Hue lights you want updated have power at the wall.
An update can't reach a bulb whose wall switch is off.
Reboot the Bridge and retry.

Unplug the Bridge for ten seconds, plug it back in, wait for all three lights.
Then open the Hue app's software-update screen and start the update again.
A clean retry succeeds most of the time.
Update in smaller batches.

If lots of bulbs and accessories need updating and the mesh is marginal, the push can choke.
Let the Bridge update first, then let the bulbs update in waves rather than all at once — leave the app open on the update screen and give it time.
Fix any unreachable devices first.

An update won't apply to a bulb or sensor showing as unreachable.
Sort those out — power-cycle the bulb at the wall, move a relaying Hue light back, reboot the Bridge — then run the update once everything shows as connected.
Wait and try later if it still fails.

Occasionally Philips' update servers are busy right after a release.
If the Bridge has steady internet and devices are all reachable but the update still won't complete, leave it a few hours or a day and try again.
If your Bridge is the old round v1, it won't update at all — that model has been retired.

Frequently Asked Questions

Is it safe to leave a failed Hue update and use my lights anyway?

Yes — a failed update generally leaves the Bridge and bulbs on their previous firmware, working as before.
You can keep using your lights and retry the update later.
It's worth getting it through eventually, though, since updates bring fixes and keep things compatible with the app and voice assistants — just make sure everything has steady power and a solid connection when you do.