A growing number of Mac users are encountering an issue where the “System Data” section is consuming a massive portion of their available disk space. Although this problem appears more frequently with MacOS Sequoia, some users on older macOS versions are also experiencing it. In many cases, the “System Data” folder in macOS has grown to occupy anywhere from 100GB up to 500GB of storage. Given the limited SSD sizes on most Macs and Apple’s steep pricing for increased storage capacity, such excessive use of disk space understandably causes frustration and concern. Even if you’ve upgraded to a 1TB drive, having hundreds of gigabytes consumed by System Data is clearly unreasonable.

It's important to note that not every Mac user experiences this issue. Many report that the “System Data” folder only takes up a few gigabytes—perhaps reaching into the low tens of gigabytes—which is considered normal. This article is specifically aimed at those who are facing abnormally large System Data usage and seeks to explore possible explanations and solutions.

Potential Fixes for Large “System Data” on Mac

Below are several potential solutions that affected Mac users have reported trying to resolve the oversized System Data issue:

• Restart your Mac
• Boot into Safe Mode, then restart normally
• Check for and install any pending MacOS updates
• Perform a Time Machine backup and allow it to complete fully
• Backup all data, reformat the drive, reinstall macOS, and restore from backup — time-consuming but effective for some
• Clear local caches, Spotlight cache files, and delete old iOS/iPadOS backups stored locally
• Reduce Safari tab usage or close unnecessary tabs — too many open tabs may trigger memory swapping which contributes to disk usage in /System/Volumes/VM/

Sometimes simply restarting the Mac can reduce System Data size, while other times it does nothing. Installing system updates might fix the problem or, in contrast, cause it to return or worsen.

Some users have found temporary success by booting into Safe Mode and then rebooting back into normal mode. However, the bloated System Data often returns after some time. Here's one example from an Apple support forum:

“I’m dealing with the same issue. After spending over an hour on the phone with Apple Support last month, we discovered that booting into Safe Mode helped. My System Data dropped from 365GB down to 45GB. I changed my Time Machine backup frequency from daily to weekly thinking that was the source of the issue, but I still find myself needing to enter Safe Mode every couple of weeks.”

In my own experience, after updating to MacOS Sequoia 15.5, my System Data ballooned to 100GB. Despite trying various approaches—restarting, Safe Mode, installing updates, clearing caches, deleting old backups, even using third-party cleanup tools (many of which aren’t trustworthy)—that 112GB of System Data remains unchanged.

Why Does “System Data” Take Up So Much Space?

The reason behind the unusually large “System Data” folder isn't always clear.

In some cases, bloated caches and temporary files—including CoreSpotlight metadata and com.apple.mediaanalysisd caches—are to blame. While manual cache cleaning may help, it doesn’t always resolve the issue completely.

Some users say they notice a spike in System Data after moving large files to the Trash in MacOS Sequoia. Others observe significant growth after backing up an iPhone or iPad to their Mac. There doesn’t seem to be a consistent pattern across all cases.

Is This Issue Limited to MacOS Sequoia?

While reports of oversized System Data are especially common among MacOS Sequoia users, indicating a possible software bug yet to be fixed, earlier macOS versions also show similar complaints.

It's worth noting that this is not a new or unique problem exclusive to Macs. iOS and iPadOS devices have long suffered from unexplained increases in "Other" and "System Data" storage. What makes this particularly frustrating for Mac users is that despite having access to the file system, tracking down and resolving the bloated System Data folder is still difficult.

Searching Apple Support forums for “System Data” yields over 9000 results. Discussions on Apple’s official forums, MacRumors, and Reddit echo similar frustrations. No definitive explanation or solution exists yet. One user described how 68% of their 1TB drive was taken over by System Data: “I've opened a case with Apple Support. I've spent hours trying to figure this out, including three hours on the phone with their team. I've run multiple diagnostics and shared the logs hoping they’ll identify the root cause. Right now, 680GB of my 1TB drive is being used by system files.”

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Have you encountered issues with the “System Data” folder taking up an abnormal amount of storage on your Mac? Did this occur only after upgrading to MacOS Sequoia or did you see it on previous versions as well? Were you able to resolve it? If so, did any of the above methods work for you? Please share your thoughts and experiences in the comments below.

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