macOS 15.1 Time Machine Could Not Complete Backup -"Some Files Were Unavailable Message"

Ever since I upgraded to macOS 15.1 I periodically get this error message. Nothing has changed except for the OS upgrade. This occurs at some point on both Backup drives. Once I see this error message I just perform the backup manually and have no problem. It looks like it is happening when the laptop has gone into sleep state. I never see this problem if I'm using the laptop and a backup happens. I also have no idea which files are causing the problem. Both backup drives have a Bkup partition and no space issues.


Anyone else encounter this problem?

MacBook Pro (M2 Pro, 2023)

Posted on Nov 9, 2024 9:46 AM

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Posted on Dec 6, 2024 6:35 AM

I resolved the issue after working with an Apple support person. I have an MBP M1 Pro with MacOS 15.1.1. and I had failures with TM both on NAS and hard wired backups. My workaround, as per the boards, was to to turn off the MacOS Firewall to let the backups work to completion.


However, I also have a cyber security software which includes a firewall of its own. There is a conflict between its firewall and the MacOS one starting with Sequoia 15.x. After I turned off the security software firewall and left the Mac OS one active, all TM backups work without error. The 3rd party cyber security software firewalls need to be updated for Sequoia.

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Question marked as Top-ranking reply

Dec 6, 2024 6:35 AM in response to mfein

I resolved the issue after working with an Apple support person. I have an MBP M1 Pro with MacOS 15.1.1. and I had failures with TM both on NAS and hard wired backups. My workaround, as per the boards, was to to turn off the MacOS Firewall to let the backups work to completion.


However, I also have a cyber security software which includes a firewall of its own. There is a conflict between its firewall and the MacOS one starting with Sequoia 15.x. After I turned off the security software firewall and left the Mac OS one active, all TM backups work without error. The 3rd party cyber security software firewalls need to be updated for Sequoia.

Nov 9, 2024 10:56 AM in response to mfein

Time Machine IMHO is to basic! It seems to every upgrade start over and start a new full disk backup, every Mac OSX and in the Mac OS systems! This is why I went for third party systems with third powered backup programs and only went Silicon us when they updated their software and it pick up right where it stopped before the upgrade!

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macOS 15.1 Time Machine Could Not Complete Backup -"Some Files Were Unavailable Message"

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