How to reduce System Data size after using Arq Backup

Question

How to reduce System Data size after using Arq Backup

I have a MacBook Air 15-inch, M3, 2024 running MacOS Tahoe 26.1.

I recently installed Arq Backup as I got sick of Time Machine backups failing for unknown reasons and forcing me to start all over again.

Arq seems to do a good job and doesn't fail but I noticed my Mac's System Data, under Settings > Storage, has grown from 90 GB to 462 GB since I started using Arq. This is out of my main 1 TB Macintosh HD drive.

Does anyone know how to reduce this to a manageable size? Or if there's a setting I need to tweak either on my Mac or on Arq? Arq Support told me to ask Apple as nobody knows exactly what they put in System Data.

Thanks in advance!

MacBook Air 15″, macOS 26.1

Posted on Dec 5, 2025 10:10 PM

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Answer 1

Dec 6, 2025 1:15 AM in response to alexfromst ives chase

Your System Data grew from 90 GB to 462 GB because Arq backups caused large APFS snapshots and temporary storage to accumulate. macOS counts all of this as “System Data.”

Fixing it requires deleting APFS snapshots via Terminal, clearing Arq temporary directories, and rebooting.

Once cleaned, System Data will drop back to normal.

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Answer 2

Owl-53

Level 10

102,205 points

Dec 6, 2025 1:32 AM in response to azaksalmarzur28

azaksalmarzur28 wrote:

Your System Data grew from 90 GB to 462 GB because Arq backups caused large APFS snapshots and temporary storage to accumulate. macOS counts all of this as “System Data.”

Fixing it requires deleting APFS snapshots via Terminal, clearing Arq temporary directories, and rebooting.

Once cleaned, System Data will drop back to normal.

Where are the instructions to delete the "Arq " Snapshots ?

You can do better that just make a suggest without providing detailed instructions - no

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Answer 3

Owl-53

Level 10

102,205 points

Dec 6, 2025 1:41 AM in response to alexfromst ives chase

Reducing System/Volume/Data is a common question.

1 - System data taking too much in MacOS Sono… - Apple Community

2 - Time Machine Local Snapshot won't delete - Apple Community

3 - Over 60% storage blocked by System Data - Apple Community

How to free up ‘System Data’ and other storage on your Mac from a fellow colleague @ neuroanatomist

Use another application to see where space is being used Storeograph on the Apple Apps Store

View APFS snapshots in Disk Utility on Mac

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Answer 4

Owl-53

Level 10

102,205 points

Dec 6, 2025 1:58 AM in response to alexfromst ives chase

You should be aware

The Apple Support Community Forums are sometimes visited by AI / LMM / ChatBots.

The usage of AI / LMM Chatbots , in and of itself has a time and place and is not bad.

Though, “ Material submitted must be your own work or work to which you have a license. By posting a Submission, you warrant and represent that you own or otherwise control all of the rights to the information contained in your Submission”

AI / LLM are basically a Super Version of Predictive Text which is based upon a Data Set.

When that Data Set is based upon older data points, the outcome of the response will be equally out dated and / or unreliable

AI is also the newest form for Data Mining by Large Corporations.

Suggest being very careful about this.

Some suggestions can be incorrect, misinformed , incomplete, impossible to do, out right wrong

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