Apple watches cannot be updated to watchOS 26.6 after iPhone gets updated to iOS 27

Fixed: What actually fixed it: a hard reset from the watch's physical buttons, not through the Watch app or Settings.

1. Press and hold the side button until the power-off icon appears in the top right.

2. Press and hold the Digital Crown until "Erase All Content and Settings" appears.

3. Tap Reset, then confirm by tapping Reset again.

After that, pairing and setup went through without the update loop. Apple chat/phone support and in-store Geniuses couldn't resolve it any other way — this button-based reset was the one thing that worked.

Hello everyone,

I recently struggled with an update loop on my son's Apple Watch SE 2 (managed via Family Sharing on my iPhone 17). After updating my phone to iOS 27, I couldn't connect to the watch (which was on watchOS 26.2) through the Watch App.

When I tried unpairing and setting it up again, I got stuck in a loop where it forced a watchOS 26.6 update but repeatedly failed with an "Unable to install update" error.

Here is how I finally solved it:

1. I paired the watch with a friend's iPhone running iOS 26.6.1.

2. On that iOS version, I was able to skip the update during setup. This option is presented.

3. Once set up, I went into the watch's storage menu and deleted the partial watchOS 26.6 download.

4. I unpaired the watch from my friend's phone.

After that, I was able to pair it with my own iPhone successfully. The update still took about 1.5 hours to complete, but it worked without any errors. It seems like a corrupted partial download was the root of the issue.

I hope this helps anyone else experiencing the same problem!

Dave

Update : I was stuck on that update loop but I was able to use my moms iPhone that had iOS 26 and I paired my watch with her phone , it worked , I was able to bypass the update, I then went into storage on watch and cleared that watch os 26 update that was stuck in a loop. I then unpaired on my phone, paired it back to mines and it updated it took like 1 hour , make sure Bluetooth is off so it wont slow down process , once it starts to install turn it back on . This worked for me , I hope it helps someone else.

This is exactly what worked for me on two watches. Wouldn’t update to 26.6 on an iOS 26 phone, would not let me bypass the update when pairing with an iOS 27 phone. Hard reset did not work.

I had to pair to a phone with iOS 26-something.

Then ON THE WATCH (not in the watch app) go into SETTINGS > GENERAL > STORAGE and delete the corrupted watchOS 26.6 update file.

Then start the update to 26.6 process again on the iOS 26 phone through to completion.

Once it’s updated to 26.6 on the older iOS phone, unpair from that phone.

Then pair with the newer iOS 27 phone, and it’s clear sailing! But what a PITA!

This is exactly what worked for me on two watches. Wouldn’t update to 26.6 on an iOS 26 phone, would not let me bypass the update when pairing with an iOS 27 phone. Hard reset did not work.

I had to pair to a phone with iOS 26-something.

Then ON THE WATCH (not in the watch app) go into SETTINGS > GENERAL > STORAGE and delete the corrupted watchOS 26.6 update file.

Then start the update to 26.6 process again on the iOS 26 phone through to completion.

Once it’s updated to 26.6 on the older iOS phone, unpair from that phone.

Then pair with the newer iOS 27 phone, and it’s clear sailing! But what a PITA!

Finally, I was able to resolve the issue.

After updating my iPhone to iOS 27, I could no longer update my Apple Watch Ultra (1st generation) from watchOS 26.2 to watchOS 26.6. I repeatedly received the attached error message.

Here is what worked for me:

1. I used my wife’s iPhone running iOS 26.5.2.
2. I paired and activated the Ultra 1, then chose to skip the watchOS update during setup. (This option was not available when setting it up with iOS 27.)
3. I deleted broken watchOS update package in watch storage.
4. Once setup was complete, I updated the watch to watchOS 26.6 without any issues (I managed update on my watch, not via iPhone Watch app).
5. I erased the watch and unpaired it from my wife’s iPhone.
6. I then paired and activated it again using my iPhone running iOS 27. Since the watch was already updated, the problematic update step was skipped.

I also noticed several issues with the Watch app on iOS 27. For example, I could not configure the Modular watch face smoothly in the app. Configuring the face directly on the watch worked correctly.

My general advice: don’t rush to update to iOS 27. It may be worth waiting a couple of months - perhaps until iOS 27.2 or 27.3 - before upgrading.

I was stuck on that update loop but I was able to use my moms iPhone that had iOS 26 and I paired my watch with her phone , it worked , I was able to bypass the update, I then went into storage on watch and cleared that watch os 26 update that was stuck in a loop. I then unpaired on my phone, paired it back to mines and it updated it took like 1 hour , make sure Bluetooth is off so it wont slow down process , once it starts to install turn it back on . This worked for me , I hope it helps someone else.

This is exactly what worked for me on two watches. Wouldn’t update to 26.6 on an iOS 26 phone, would not let me bypass the update when pairing with an iOS 27 phone. Hard reset did not work. I had to pair to a phone with iOS 26-something, then go into storage ON THE WATCH (not in the watch app) and delete the corrupted 26.6 update file. Then start the update to 26.6 process again on the iOS 26 phone. Once it’s updated to 26.6 on the older iOS phone, unpair from that phone, pair with the newer iOS 27 phone, and it’s clear sailing! But what a PITA!

Here's what worked for me on a Series 8 watch. No need for an older iPhone or a full reset:

1. Turn off phone (maybe turning off bluetooth is enough, but I turned off my phone just to be safe)
2. Put your watch on the charger.
3. On the watch, go to Settings -> Storage -> iOS 26.6 - delete the file.
4. On the watch, go to Settings -> Wifi - make sure it's connected to wifi
5. On the watch, go to Settings -> General -> Software Update, download and install 26.6 directly on the watch, without going through the phone. This might take quite a while. I had to hit the "install" button once after downloading, and after that it took a good 45 minutes to complete.
6. Turn your phone back on after the update completes. Notifications etc. will work again.

I recently updated my iPhone to iOS 27 before updating my watch to 26.6 had the same issue, was in the update error loop, I called Apple Tech support. It was useless. They had no idea. They just kept telling me to do the same things I had already done, and the next Apple Genius appointment wasn’t until Friday.

The only thing that worked was I had older iPhone at home. I reconnected that, paired my watch with that phone, and then unpaired and paired to current phone.

The existence of the corrupted watchOS 26.6 file was altogether preventing the update to 26.6. By pairing it with the 26 iOS phone (which allows pairing without requiring update to watchOS 26.6 to complete the pairing) I was able to delete the corrupted watchOS 26.6 file from within the watch storage and then re-do the update on the 26.x phone without the corrupted file interfering. The iOS 27.x forces update to watchOS 26.6 in order to pair the watch to the phone, but it couldn’t update with the corrupted file still existing on the watch. Hope that helps!

Thank you, THANK YOU, Luheesa. This worked for me! FINALLY! I’ve been extremely frustrated and exhausted running around the house to different phones and my watch plugged into their chargers and trying unsuccessfully all the other advice on this forum. But the one step I think the rest were leaving out is what you said: “Then start the update to 26.6 process again on the iOS 26 phone through to completion.” Thanks for leaving such clear instructions that work.

mine eventually worked after I left my watch off for almost the whole day! It was just a retry

Update: I’ve even pulled out an old iPhone 13, updated it to iOS 26.7, and I still get the same error message the OP of this thread is getting when I try to pair (which REQUIRES am install of Watch os26.6 update) to iPhone 13 and iOS 26.7. I’m not a tech-savvy guy, but that makes me think it’s a WatchOS 26.6 update issue, not an iOS 27 issue. To further that belief, I have two watches - a Watch series 6, and a Watch Ultra series 1. Both of them WERE paired to both of my iPhones, but now neither of them will pair to *either* phone (running either iOS 26.6 or iOS 27) - unless I update to WatchOS 26.6 - which gives me the error code and won’t install. But….why did my Watch 6 stop paring with my iPhone 13 Pro Max and 17 Pro Max in the first place when I haven’t even tried to update IT to WatchOS 26.6 like I did my Ultra 1? I’m confused, and broke from all the Apple products I buy.