macOS update stuck or failed to personalize

After this, the update either completes normally or you know for certain it needs Recovery, instead of guessing while it sits there.

Why this happens

On Apple Silicon Macs, installing macOS involves a step Intel Macs never had: the Mac contacts Apple's signing server and requests a fresh, "personalized" signature for the new system, tied to your specific chip's unique identifier. Apple's own security documentation describes this directly — it's part of how the Signed System Volume gets verified at every boot afterward. If that network round-trip to Apple's servers gets interrupted, or the Mac doesn't have enough free space to complete the write, the process reports back "failed to personalize" rather than quietly retrying. There's no equivalent step on Intel hardware, which is exactly why this specific error text is Apple-Silicon-only.

The generic "stuck at X minutes remaining" progress bar is a separate, much older issue — the installer's time estimate has been unreliable for years, on any Mac, and genuinely freezing is much rarer than the progress bar simply being wrong. Don't confuse the two: one is almost always fine to wait out, the other means the attempt actually failed and needs a real retry.

Fix it

1. If the progress bar looks frozen at a specific time remaining but nothing has errored, give it real time before intervening — 30 to 60 minutes with zero movement at all is a reasonable point to start suspecting a genuine stall; less than that is very likely just the estimate being wrong, not a freeze.

2. If you actually see "failed to personalize," check your internet connection and available storage before retrying — both are named directly in Apple's own guidance for this error. From Terminal, confirm free space quickly:

   ● Reads the system

   What it does: prints disk capacity and free space for the startup volume.

   After: nothing changes, this only reads.

   df -h /

   Copy

   macOS installers typically want tens of gigabytes free, not just enough for the download itself — if Avail is low, that alone can be the whole explanation. Also worth ruling out: a VPN, proxy, or security tool intercepting the connection to Apple's servers.

3. If it fails again after confirming both of those, install from macOS Recovery instead of the System Settings updater — hold the power button at startup until "Loading startup options" appears, choose Options, then reinstall macOS from there. Recovery bypasses whatever third-party software or session state may have interfered the first time.

4. If Recovery-based installation also fails to personalize, the Mac's own firmware may need to be restored directly — Apple's documented path for this is reviving the Mac's firmware via Apple Configurator or a Finder-connected second Mac, specifically for Apple Silicon and T2 Macs whose firmware has gotten into a state the installer can't update past. That's a distinct process from a normal reinstall — follow Apple's current instructions for DFU/restore mode rather than improvising it.

Still broken?

• Check whether this is a known issue with the current macOS version
• The update finished but the Mac feels slow afterward

Verified on

Related problems

• What's broken in macOS 26 on Apple Silicon (so far)
• Mac running slow after a macOS update