Mac OS Tahoe 26.4 installation stalling

Confirm that you have sufficient storage space available ('preparing' includes unpacking the update to a much larger size than the actual download), then try again.

boccio wrote:

I have 114 GB available on the Hard Disk and 8 GB of RAM. I never had this problem before.

Apple recently installed Tahoe 26.3.1 (a) for security reasons. That isn't causing the problem is it?

Software on the computer interfering with the download / installation process including AntiVirus Software

Notation: Disabling the AV Software may or may not solve the issue.

Removal of the AV Software may increase the chances of the download to perform as expected.

Running behind a VPN which may increase Packet losses or corruption of the download 

Turn off any Third Party Two Way Firewall and try again 

Worst case - Restart in Recovery Mode and choose Reinstall macOS. 

This in theory will pull the latest version of macOS this computer qualifies to run 

boccio wrote:

Well it turns out you just have to be very, very patient - not a good thing for me! On my MacBook Air M3 I had to wait (when it said 5 minutes) 47 minutes and then it went to completion. On my MacStudio M1 I had to wait only 18 minutes. I would really like to know what the installer is actually doing during those time periods???? Apple needs to straighten that process out or change the times that get specified!!!

Check your internet connection

The installer needs a stable internet connection to download macOS and get firmware and other information specific to your Mac model. Make sure that your Mac is connected to the internet.

Install from macOS Recovery

To ensure that no other software on your Mac can interfere with installation, install macOS from macOS Recovery.

For the same reason, if you’re installing via the App Store or Software Update instead of Recovery, it might help to start up in safe mode before installing.

I my case

I M2 Desktop moved from 30 minutes to 18 minutes in about 2 minutes

Moved from 18 to 5 minutes within 3 minutes

Moved from 5 Minutes and wait 10 minutes

Auto reboei several times and presto, installed

M4 Desktop, 30 minutes to 18 minutes within 1 minute

18 to 5 minutes within 3 minutes

5 minutes and pause 5 minutes

5 minutes to auto reboot several time and again presto Tahoe 26.4

Will attempt the M4 15" MBA later today and expect to have similar results as the M4 Desktop

Go figure

I know with the last two Tahoe updates 26.3 & 26.3.1, my M-series Mac took an extremely long time (did not time it) to install the update which appeared to have 4 soft reboots (no chime, screen went black progress bar started at zero & quickly filled to its last point)......before the fifth & final full reboot which had a startup chime. I have never seen any of the other updates do this. If the 26.4 update behaves in a similar manner, then you may never have noticed this change before.

Computers with "invasive" third party software may end up causing problems or extend the length of time involved since those "invasive" apps interfere with the normal operation at a very low level. "Invasive" third party apps include anti-virus software, cleaning/optimizer apps, and third party security software.

boccio wrote:

I have 114 GB available on the Hard Disk

FYI, the "Available" storage value shown every where in macOS should be ignored since it is very misleading. The only important & accurate storage value is the Free space value which is only shown in Disk Utility. In macOS "Available" is not synonymous with Free.

You may have had much less that 114GB of Free storage space at the time.

Same problem. Stopped after the download appeared to be complete.

I had to stop it (hit "x") and start the update process again.

Second time it worked.

Bad news: "Touch ID & Passwords" was no longer in the Settings menu.

Doing a search didn't find it, either !?

Big time BUG

Stalled for how long?

One of my Macs paused there for about 15 minutes, then completed. It also started with a time remaining estimate of 4 hours, which dropped to the 5 minute mark in about 10 minutes, so it seems macOS is not very good at estimating the time. Similarly, my WatchOS update had 8 minutes left in Preparing Update for close to 30 minutes.

Mac_Cat wrote:

Same problem. Stopped after the download appeared to be complete.

I had to stop it (hit "x") and start the update process again.

Second time it worked.

Bad news: "Touch ID & Passwords" was no longer in the Settings menu.

Doing a search didn't find it, either !?

Big time BUG

Since the updated was installed.

How many times has the machine been restarted ?

Barring that

Restart the computer in Safe Mode 

Do the issues persist ?

Sometimes a Safe Boot followed by a Normal Boot will just put things right.

I waited 25 minutes before giving up the first attempt.

As for file transfer estimates-they have rately beeb accurated! Its always just a wild guess. The most you can hope for is that its still making progress. Odfly, I have never seen one hang before, so this is a new experience. Servers must be overloaded ….

jaimindave wrote:

Right now I am facing the same problem on my M4 MacBook Air

15 " M4 MBA, 16 GB UnifiedRAM / 512 GB SSD

Via 6E Wifi to Fibre Optic connection

Start of download via Software Update applet @ 16:17 hrs EDT to final reboot and log in @ 16:38 hrs EDT

Go figure

Right now I am facing the same problem on my M4 MacBook Air