How can I troubleshoot or fix when macOS Photos app import from a connected iPhone gets stuck on "Preparing to import from..."?
- iMac Retina 5K 27-inch 2017, macOS Big Sur 11.2.3
- iPhone 12 Pro, iOS 14.4.1
Setup: iPhone is connected to the iMac with a USB-Lightning Cable
Photos app on MacOS import from connected iPhone appears to be stuck on "Preparing to import from" and never makes progress.
Steps to reproduce:
- Launch Photos
- Unlock iPhone
- Connect iPhone to iMac with cable
- Click the name of the connected iPhone under "Devices" section of Photos
- Photos shows a message: Preparing to import from "Device_Name" where Device_Name is the name of the iPhone
- Wait... forever...
- Imports previously used to work between these devices.
- The Photos Library has been repaired multiple times by opening Photos while holding Option-Command.
- The iPhone successfully synchronizes and backs up via the Finder when connected.
- Swapping out cables does not change the behavior.
- Restarting the iMac, iPhone, or macOS Photos app does not solve the problem.
- iPhone has over 40,000 items (photos, live photos, videos, etc.) and a few hundred are new items since the last import while the others are already imported.