TM says I have 8GB available space when I actually have 8TB. How do I get TM to see the entire drive?

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TM says I have 8GB available space when I actually have 8TB. How do I get TM to see the entire drive?

Due to the macOS 26 update, I purchased a new NAS 8TB hard drive to use with TM. I installed the drive, didn't limit the folder size or size of the file when I selected the backup disk. I immediately got the "disc not recommended for backup" warning, but I went with the disk anyway. When I started the backup it said I had 8gb available. After it failed because "the backup disk is full" it says I have 838.9mb available. What happened to the rest of the space? How do I get TM to recognize the full 8TB size of the drive?

Mac Pro (2019)

Posted on Jan 22, 2026 7:08 PM

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Answer 1

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CarlTipp Author

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Jan 27, 2026 10:52 AM in response to FishingAddict

Thanks, I checked all that and everything seemed to line up with what I was doing on the Mac side. I eventually reformatted the backup drive, resetting it to the original factory settings, and started over with the drive setup. Funny thing is that setup steps were different than the first time I had set it up. Through the second setup I found a screen that said the folder size was limited, must have been the factory default setting. I changed it to unlimited and that fixed the problem.

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Answer 2

Jan 25, 2026 6:23 PM in response to CarlTipp

I immediately got the "disc not recommended for backup" warning, but I went with the disk anyway.

This should have clued you in that something is not right with this setup. I would review the following information carefully and start over:

Backup disks you can use with Time Machine - Apple Support

Types of disks you can use with Time Machine on Mac - Apple Support

Backups are so critical that you want to make sure that everything related to a Time Machine setup is a recommended configuration.

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TM says I have 8GB available space when I actually have 8TB. How do I get TM to see the entire drive?

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