#Couldn t unmount disk time machine update#

UPDATE – 10/07/21 – If you are finding this article, it is most likely because you have Upgraded from macOS Mojave to Big Sur or installed the latest Big Sur 11.6 update. If you are seeing this issue, please contact Apple.

#Couldn t unmount disk time machine how to#

How to fix this issue – Erase & Reinstall macOS 13 How to fix this issue + retain your data!.You have 2 different options for fixing this issue.

#Couldn t unmount disk time machine install#

Can I get my Mac out of this install loop? What happens when the upgrade installer runs out of space? How can I prevent this from happening to me? How can I tell if my Mac is affected by this issue?

Are the Big Sur Updaters also affected? (example 11.1 > 11.2 delta update) Big Sur 11.2 Upgrade not enough free space problem. Security Update 2019-001 update causing data loss on some T2 Mac computers /mojave-2019-001-security-update-causing-data-loss-if-interrupted/ Table of Contents If you installed the 2019-001 Security Update and the Mac was encrypted, the user could be locked out. The 2019-001 Security update issue was close to this one. This isn’t the first time I’ve reported on update issues that could cause data loss. Macintosh Full report and Deep Dive into the issue + Multiple fixes and workarounds to save your data and let the Big Sur Update finish! Past macOS update issues like this one This led me to investigate this issue further. The reason behind the traffic increase was because the M1 personalization error message was very close to the new error.īig Sur Upgrade out of space error = An error occurred preparing the software update.īig Sur Upgrade out of space error = An error occurred applying the software update.Īpple Silicon M1 personalization error = An error occurred preparing the update. I noticed an increase in traffic to this article. Reports started to roll in saying that the Big Sur Upgrade failed and the only way to fix it was to erase and reinstall macOS. The first signs that this is becoming a larger issue came after the macOS Big Sur 11.2 update was made available. I’ve been trying to get a handle on this issue for over a month now. This leaves you unable access your data! I will go over all the details below and show you a fix at the end. Your hard drive is now 100% full and the installer is now stuck in a boot loop attempting to finish the install. The upgrade will start even if you only have 1% of free space left and will fail.

You should see a pop up message showing you how much space is needed before you can attempt the upgrade again. If the installer finds that you do not have enough free space for the upgrade, it will stop and not let you continue. Quick Summary – When you start the macOS Big Sur upgrade, the installer should first check to make sure your Mac has enough free space available. UPDATED 10/07/21 – Latest Updates!!! – For the latest information be sure to check the UPDATES section below. If FV2 encryption is enabled, you will be locked out of your data!

The upgrade will start, then run out of space and fail. The macOS Big Sur upgrade is not checking to make sure enough free HD space is available.