Apple Watch Ultra won't pair with iPhone 17 Pro – "Unable to Install Update" at the watchOS update step
Hi all,
I have an Apple Watch Ultra (49mm) that was working and paired fine before. I left it switched off for a long time. When I turned it back on, it would no longer connect to my iPhone, which is now a new iPhone 17 Pro.
What I've done so far:
- Unpaired/removed the watch from the Watch app on the iPhone
- Removed the watch from the iPhone's Bluetooth device list
- Factory reset (Erase All Content and Settings) on the watch itself
Now, every time I go through pairing, it reaches the step where it has to update the watch to watchOS 26.6, and then it fails with:
"Unable to Install Update – An error occurred installing the latest version of watchOS on your Apple Watch."
After that, the watch goes back to the Apple logo / pairing screen, and I'm stuck in a loop.
Things I've already tried:
- Force restarting the watch (side button + Digital Crown) and restarting the iPhone
- Keeping the watch on its charger and the iPhone right next to it
- Using mobile data instead of Wi-Fi, and a different network
- Resetting network settings on the iPhone
- I checked my home DNS filter (Pi-hole): all Apple update domains (mesu.apple.com, gdmf.apple.com, updates.cdn-apple.com, xp.apple.com, albert.apple.com) are allowed and resolving, so it isn't being blocked
My questions:
1. Is there any way to skip the watchOS update during pairing, or to update the watch some other way?
2. Has anyone fixed this "Unable to Install Update" loop when the watch is on a very old watchOS version?
3. Or is the only option to take it to Apple / an authorized service provider for a restore?
Thanks in advance for any help!
