Apple Watch on iPhone is stuck on "preparing the update"

There is a simple solution, simply open the watch app, go to general, scroll down to storage, select the watch OS update and delete it. You can now go to Software Update in the watch app and it will ask you to download it again

I figured out the issue with the 10.2 update not loading to my Ultra 2. I turned off the vpn on my iPhone, tried and it started downloading immediately. So if you have a vpn on your phone, try turning it off to do the update…

Same thing. I did the following:

1) turn off VPN and the “on demand connect” setting in the VPN you’re using.

2) turn off wrist detection in watch settings.

3) plug in iPhone and watch.

4) hard reset both devices.

5) restart install from settings on watch.

6) do not let watch screen go off and lock until update complete (i just rolled the update screen back and forth).

This finally worked for me about 10 minutes ago. I tried several other combinations of the suggestions above, but this is the one that worked for me.

Not sure if it's relevant, but mine (Apple Watch Ultra 2) was stuck in this mode for a couple of weeks trying to update 10.3. The watch functioned fine. Today I decided to try to update to 10.3.1; however, it was still stuck in "preparing the update" from 10.3. I did a hard reset of the watch while it was on the puck charger. Before logging into the watch, I used my iPhone (iPhone 15 Pro Max) and tried to push the watch update. It notified me that I needed to unlock the watch first. While still on the charger I unlocked my watch. Immediately the update resumed, but for 10.3.1. The download and preparation completed and it then prompted me to do an install. The install completed as normal and my watch is now updated to 10.3.1.

Same issue on Ultra2 and 10.4. Tried multiple shutdown/restarts on 15promax. No success. Finally tried shutting down WiFi and using cell service. Broke free and completed install.

Switched off WiFi and the preparing freeze "thawed" !!! finished within a few minutes.

Reset the phone and try again.

Try using a different wifi network; office, neighbor, cousin, grandma, library, coffeeshop.

I just switched to Cellular Data and it worked :)

If the iPhone is up-to-date with iOS 17.2, then try a different wifi network; office, library, coffeeshop.

Also a hard reset for them both.

FWIW, I just ended up resetting my WatchSE and the update completed fine.

I performed a hard reboot on both of my devices and for an update that’s just under 1GB it’s sure taking a while

The update can only be installed when the watch is on its charging puck.

M1 Mac mini, macOS 14.1.2;  Watch, series 7 GPS/cellular, watchOS 10.1.1; iPad Pro 2nd Gen, iPadOS 17.1.2; iPhone 12 Pro, iOS 17.1.2; TV 4th Gen, tvOS 17; HomePods, audioOS 17.1.1 and Airport Express w/ Airplay 2

That makes perfect sense!

watchOS versions are regionally specific. Certain watch features that are legally classed as medical functions are only in an update for countries where government agencies allow them.

A VPN would confuse Apple servers as to where you are and which update to allow you to download.

An example would be the ECG function. Some folks have reported buying a watch in the US where the ECG function is allowed. Later they took the watch to a country that had not authorized the ECG function and the first time that they updated their watch in that country the ECG app was removed!

You should NEVER use a VPN when doing an update/upgrade to an Apple OS!

The software for each device, especially the Watch, is region/country-specific and the VPN makes it so the servers can't determine which OS to offer.