iTunes - Downloading iOS 9.2.1 Timed out on Processing File

Hello.

I was attempting at updating an iPad Air to 9.2.1 from 9.1 last night via iTunes.

After the 1.8GB file download switched from "downloading" to "processing" (even though the counter didn't appear to be fully at 1.8GB) iTunes said it was unable to update the iPad / timed out. No more information or error message (sorry I do not have a screenshot). Since the download was a full 30 minutes, I did not attempt again. It is the first attempt at an iOS update since a clean install of El Cap 10.11.3.

1. Does this indicate a problem with iTunes processing the iOS file or does it indicate a wifi issue? My download speed is slow, but the error appeared only after the display changed to "processing." iTunes has successfully updated apps and processed those tiny files.

2. I do need the iTunes update as I am attempting to solve some bugs that an OTA update may not address.

3. I assume I need to remove the file from the device

Thanks in advance,

H