Unable to Pair Apple Watch – “Unable to Install Update” Error

I finally found the solution to the issue I was facing while pairing my Apple Watch.

On my old iPhone, I had already downloaded the watchOS 26.6 update, but I had not installed it. Without completing that update process, I unpaired the Apple Watch from my old iPhone and tried to pair it with my new iPhone. I believe this was the reason I was getting the “Unable to Install Update” error.

I then connected the Apple Watch back to my old iPhone, deleted the downloaded watchOS 26.6 update, and unpaired the Watch properly.

After that, I paired the Apple Watch with my new iPhone and downloaded the update again from the beginning. This time, the update installed successfully, and finally my Apple Watch was successfully paired with my new iPhone.

thank you so much