Have a look at this discussion thread on a similar situation:
(The advice suggested there may help you with your watch.)
Apple Watch update stuck on preparing - Apple Community
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When you sign up with your Apple Account, you can provide valuable feedback to other community members by upvoting helpful replies and User Tips.
When you sign up with your Apple Account, you can provide valuable feedback to other community members by upvoting helpful replies and User Tips.
Have a look at this discussion thread on a similar situation:
(The advice suggested there may help you with your watch.)
Apple Watch update stuck on preparing - Apple Community
Have a look at this discussion thread on a similar situation:
(The advice suggested there may help you with your watch.)
Apple Watch update stuck on preparing - Apple Community
My Apple Watch Series 3 has been stuck on this preparing screen Any way to solve it?