Short answer-:- Many or most of the suggestions here will work to get past the update error. With one critical modification. The instructions to place your watch on its charger should not be taken lightly. What they mean is that you should place your Apple Watch on an Apple watch charger, not a generic watch charger. It does not matter the brand. And for insurance purposes, also connect your iPhone to an Apple charger. So, if you have already encountered the error, here is my long answer and suggested method. Long answer-:- I, like many people reporting here, went through the frustration of attempting to pair an Apple Watch to an iPhone. For the record, I am in IT and I think I am semi-capable of pairing a watch to a phone. In my case, an Apple Watch 5 to an iPhone 12 Pro Max. I have done this with 3 other Apple watches, and several iPhones. The iPhone was pre-updated to the latest iOS. As per instructions, both the iPhone and the watch were charged past 50%. On my first attempt to pair the two, the error was encountered. I verified that I was connected to the internet on my PC and my iPhone. My wi-fi is not the best but not terrible (as per WiFiman, 187 Down and 19 Up Mbps) on my iPhone. Found information on resetting the watch and the Watch app, and my iPhone. Tried it again, and again, and again, and nothing. Finally, this professional IT person, with his pride hurt, had to call Apple support. After 3 calls with no success, I was sent to the Apple Store. On the first try, the agent was able to get past the error. Unfortunately, my wife and our dog had accompanied me and waited outside the store. My dog develop a bad nervous crisis because of people with masks, and started vomiting, etc. Anyway, I had to walk out of the store with the update only about 25% complete. The pairing process got interrupted in our way home. Next day I tried again. Nothing. Two calls to Apple Support, and nothing. Back to the Apple Store. On the first try, it worked. What???? Then it downed on me. They were using an Apple watch charger, and I was using a generic watch charger because I like the design and convenience of it. So here is my suggested method: Update your iPhone iOS to the latest version available Charge both the iPhone and Apple Watch on their respective Apple chargers until at least 60% charge Leave them on their chargers as much as possible for the rest of the process. If you need to remove either from their chargers for easier manipulation, put them back on the chargers immediately after Hard Reset the Apple Watch to factory settings - Let it return to the pairing mode. Turn off the Apple Watch Delete the Watch application from your iPhone, and delete all the data Close all open applications on your iPhone Turn off your iPhone, wait about 30 seconds Restart your phone. Ensure that you are fully connected to your wi-fi (turn off your cell signal, and your bluetooth, search for something on the internet) Re-install the Watch application from the Apple Store on your iPhone Turn on your Apple Watch Your iPhone should detect the Apple Watch Follow the pairing instructions Do not use your iPhone while the update and pairing are still in process to reduce the chance of error Happy pairing NOTE: The software update and pairing takes about 2 hours on a good wi-fi connection. Your total time may vary depending on your connection.