Free space issue

The place to discuss Mac OS X version of MakeMKV
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NewGuy1981
Posts: 1
Joined: Wed Apr 28, 2021 7:50 pm

Free space issue

Post by NewGuy1981 »

Hello everyone, new guy here. I looked for this issue before posting, but I apologize if it's a repeat.

I am trying to rip my blu-ray collection on my M1 Mac Mini w/ Big Sur. I've run into a bit of an issue. My computer has 145gb of free space on it, but according to the MakeMV program, there are only 21gbs of free space left, which is not enough to rip the movie I'm working on.

When I started (about 4 movies ago) it said I had 71gb of free space on the drive. While that was less than I knew my computer had, it still worked. It's slowly decreased to an unusable figure. If there is a cache folder, I'm unable to find it.

Any ideas?
dcoke22
Posts: 514
Joined: Wed Jul 22, 2020 11:25 pm

Re: Free space issue

Post by dcoke22 »

How to free up storage space on your Mac https://support.apple.com/en-us/HT206996

You really should consider getting some external storage. A plain old hard drive is fast enough and cheap enough to do this sort of stuff. A blu-ray is around 30GB and a 4K UHD is somewhere between 50GB and 75GB typically. 10TB external drives are often less than $200.
T'hain Esh Kelch
Posts: 82
Joined: Thu Apr 20, 2017 5:59 am

Re: Free space issue

Post by T'hain Esh Kelch »

I've also had MakeMKV report what free space I have available on macOS wrong, for several years. Is it a clash between how the OS reports free space and what MakeMKV expects on other platforms (kibibytes vs kilobytes)?
dcoke22
Posts: 514
Joined: Wed Jul 22, 2020 11:25 pm

Re: Free space issue

Post by dcoke22 »

Modern macOS does things in the background that makes free space more complicated than it might seem. For example, there's something called Time Machine local snapshots (https://support.apple.com/en-us/HT204015). It primarily is used on laptops. It uses 'free space' on your computer's internal storage. If the Time Machine disk is unavailable (i.e. you're using the laptop at a coffee shop & your Time Machine disk is at home on your desk) it'll go on making once-an-hour backups into the 'free space' on your disk. As reported by Finder, these local snapshots don't count in the used space on the machine since they're supposed to be purged when the space is needed. How they work and where they're stored has changed as macOS has transitioned from HFS+ to APFS file systems.

MacOS is like most modern computer operating systems in that when free space on the boot volume gets low, things can often get weird or fail for non obvious reasons. This is why I generally recommend storing rips from MakeMKV on a drive that isn't your boot volume. Either on an external drive or on a second data drive in your computer or on a NAS somewhere. Rips are big and a bit unwieldy and it is easy to accidentally put your boot volume into not-enough-free-space situation.
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