None of the suggestions in this thread helped me, so I had to get creative.
I bought a new m4 iPad Pro and during the setup of transferring my old iPad to the new one, the setup process forced me to do the 18.0.1 update before the file transfer would begin. I’d click “install now” after verifying the update, a waiting circle would appear and never go away. If I forced restarted the new iPad, it would go to the “transferring files” screen and hang there with no progress indefinitely. I tried this 4-5x with the same result.
The ONLY thing that fixed this for me and allowed me to successfully set up the new iPad is this:
1) Start the new iPad setup process and set the iPad up as a “new device” and do not transfer any data.
2) Once the new iPad is set up (the setup for a new device doesn’t force you to update) go into settings and update to 18.0.1. This time the update will be successful. My M4 ipad purchased in 10-2024 came with iPadOS 17.7 out of the box.
3) After the update in #2 above finishes, go into settings and “Reset and erase data” on the new iPad. This option wipes the iPad but retains the software version.
4) After the new iPad has wiped and restarted, set it up as you were originally trying to by selecting to transfer data from an old device. This time, the setup won’t prompt you to update to 18.0.1 because the device is already 18.0.1 by performing steps #1-3 above.
5) This time the setup will be successful.
It seems that iPads, even ones shipping in October of 2024, still ship with iPad OS 17.7 and it bugs out when trying to update to 18.0.1 during the setup process. Setting up as a new device, updating to 18.0.1, wiping device, and doing the transfer from old device setup fixed this issue for me. I’ve had to do this on 12 company iPads, so it doesn’t appear to be a rare occurrence.