My Free SSD Space Drops 15-20GB Every Day - Help Needed

[mymacsux]

Hi all. Long term mac user but was recently gifted a new machine which I've had nothing but problems with since day one if anyone can help. Specs are as follows:

13" Macbook Air M4 / 256gb SSD / 16gb RAM / Sequoia 15.7.7

The laptop is not not entirely my main use computer so I only really use it for a few movies/games and apps that wont run on my older day-to-day mac; and because not much ever changes on it, I know every time I switch it on I should always have ~60GB free SSD.

However, all of a sudden, at some random point, even if the laptop is totally idle, my SSD will instantly go from ~60GB free to ~45GB free. It does this every day at least once. No idea why, and I'm certain it never used to do it as I would have noticed.


Don't know if it's relevant but a short while back I upgraded to Tahoe, didn't like it, so did a full erase and Sequoia reinstall. Since then I've done several clean installs trying/failing to get fix the issue. Can't say for sure if its connected to downgrading as I don't recall it happening right away.

As you can see from the screenshots, from the General > Storage tab in Settings, my MacOS balloons from the normal ~25GB to ~40GB with System Data rocketing from ~2GB to ~7GB.

I do not use any Time Machine backups yet from Disk Utility something is making multiple 5.66GB snapshots on one of the segmented drive sections.

Restarting the computer does nothing to delete these snapshots or give me back my missing 15-20GB. The only solution I've found it booting in Safe Mode, which does fix the issue, however within a day my ~60GB drops back to ~45GB again.

I should not have to keep booting into safe mode every few hours to fix an issue that never used to exist, so any help or advice to fix this would be much appreciated.


Sorry for long post. Many thanks in advance.

 

[ry-guy]

It’s a bug. I have the same on Tahoe, brand new MacBook Air. System Data will balloon to 70 gb , i boot it in safe mode and restart it and it’s like 9gb. I tried everything, had Claude help me diagnose it and the safe boot mode was the only thing i could tie it to. It’s annoying for sure.

 

[MarkC426]

Can you select them and click the delete (-) button….?
Have you done software updates recently, they could be created for that, to save the previous state.

 

[!!!]

My only suggestion would be to use GrandPerspective/DiskDaisy/OmniDiskSweeper to find out where exactly the size is coming from. Maybe there's a runaway processes writing too much data somewhere.

 

[mymacsux]

It’s a bug. I have the same on Tahoe, brand new MacBook Air. System Data will balloon to 70 gb , i boot it in safe mode and restart it and it’s like 9gb. I tried everything, had Claude help me diagnose it and the safe boot mode was the only thing i could tie it to. It’s annoying for sure.

Can you select them and click the delete (-) button….?
Have you done software updates recently, they could be created for that, to save the previous state.

My only suggestion would be to use GrandPerspective/DiskDaisy/OmniDiskSweeper to find out where exactly the size is coming from. Maybe there's a runaway processes writing too much data somewhere.

Thanks all for the replies.

@ry-guy I didn't use Tahoe long enough to notice if this issue happened with that OS too, so for me it's really only a new thing in Sequoia but it never used to happen which is odd.

@MarkC426 I tried to delete them but I just got an error message as per the attached screenshot. I haven't done any software updates per se as I've done several full erase/resets, so it's a fresh install, all apps from the App store, with Sequoia 15.7.7 being the default version. The only "update" is a ~200mb Safari update but would be surprised if thats the cause. I've tried terminal commands to maybe stop mac doing/prompting updates in the background but -so far- it doesn't feel like they are a fix.

@!!! I've downloaded all three of those and will give them a try soon as I'm going to try and leave the mac idle/off for a day or two just to see if somehow not using it maybe resets the issue, or if it doesn't, perhaps I can pinpoint why it seems to keep happening at certain times of the day and not others.

Thanks all for the suggestions, very much appreciated indeed. Any further suggestions are welcome. Will update with any relevant info over the weekend.

 

[tonmischa]

a few random thoughts:

- if nothing else helps, you should do the nuclear option: a full DFU restore with a fresh Sequoia .ipsw. That's the ONLY option that will completely wipe all the Tahoe traces from your system.

- Have you Carbon Copy Cloner installed? It can also create Snapshots. (It can also delete them. Pretty helpful.)

- Does the System Data keep growing? (like 5 GB per day?) Or will it stay at a certain point?

- Please note, that there is a certain amount of System Data, that is needed for daily use. (Caches, Indices, etc.) These are deleted when you boot into SafeMode, but are recreated during normal use, because the Mac needs them. (System Data on my Sequoia M2 MacStudio is 49 GB for example, after almost 3 years of use. So 7 GB of System Data - like in your case - seems pretty reasonable to me. At least as long as it doesn't increase by 5 GB per day.)