TROUBLESHOOTING

iPhone Update Stuck on Preparing or Estimating Time

By iPhone Update Editorial Desk · Reviewed September 19, 2026

DO THIS FIRST

Wait 20 minutes if the phone is charging and on Wi-Fi. If the time estimate never changes, force-restart, delete the update file, and retry. Preparing includes unpacking and writing a new system volume; it is not a live progress bar.

What you are seeing

The installer sits on Preparing Update or Estimating time remaining for far longer than a normal install.

Why this happens

Preparing is disk work. A nearly full volume, thermal throttling, or a damaged staged file makes that step look frozen.

Do this in order

Confirm the screen is not just dimmed. Tap it. A moving progress bar means leave it alone.
If there is no bar movement for 20–30 minutes, force-restart using the volume-up, volume-down, hold-side sequence on iPhone 8 and later.
Delete the update and download it again while charging.
Move the phone off a hot surface. Thermal limits pause unpacking.
If Preparing fails twice, install from a computer.

If it is still broken

A loop that always dies in Preparing is a bad local stage. Stop OTA retries and use Finder or Apple Devices.

Questions this page actually answers

Is overnight “Update Tonight” safer?

It can be, because the phone is charging and idle. It does not fix a corrupt download.

Will force restart brick the phone?

No. It interrupts a stuck unpack. The next boot either resumes or returns to the previous iOS.

Next useful pages

Sources

Prepared by the iPhone Update Editorial Desk. Independent technical reference. Not affiliated with Apple Inc.