How to reduce SYSTEMDATA size by disabling Connection Activity Log in Email on Mac?

SystemDataMan wrote:

So to clean this up it’s simple. Open Email, got Window them Connection Doctor.  If your Connection Activity Log is enabled then disable it.

Select Show Logs, drag them to the TRASH ( I love saying that! ), then empty the trash.  Once done, restart the MAC and SHAZAM the issue is resolved.

Have a better day!

[Re-Titled by Moderator]

Original Title: Cleaning SYSTEMDATA

Good computing SystemDataMan !

It can be a contributing issue to "SYSTEMDATA" but not necessarily the only cause.

ref: Free up storage space on Mac - Apple Support

Have not heard reference to this issue in quite sometime— but it is a known issue.

These mail logs are not turned on by default..

I have seen anywhere from 12 GB to 700 GB of logs built up here.

ref: Mail IMAP txt Log too big, Catalina 10.15… - Apple Community

You would be safe to delete all those logs/ .txt files.

Mail>Window>Connection Doctor

System Data taking up a large amount of storage is a common question on Mac.

There is no single setting that simply “clears” System Data because this category can include a variety of files, including caches, logs, temporary files, and APFS snapshots.

If you want the most comprehensive solution, back up first, erase the Mac, and reinstall macOS.

For Apple silicon Macs, use Erase All Content and Settings.

This removes your data, settings, and applications while leaving the currently installed version of macOS in place.

Make a current Time Machine backup before erasing anything. Apple: Back up your Mac with Time Machine

Afterward, use Migration Assistant to transfer your user account rather than the entire old system, and reinstall only the applications you actually need.

If you do not want to erase the Mac, first determine what is actually consuming the space. DaisyDisk can provide a clearer view of storage usage, and Apple documents how to view APFS snapshots in Disk Utility.

The following Apple Community discussions document additional approaches. Results can vary depending on what is responsible for the storage usage:

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

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

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

•  - Running out of storage - system data is huge after upgrade to macOS Tahoe 26.2

•  - System Data consuming storage on Mac and how to clear it

•  - System Data at 114 GB AFTER deleting other files....

•  - How to free up System Data space on Mac

• Systems Data bloated

• Mac mini storage is full despite external drive and cloud documents

Also consider moving large personal files—particularly Photos, videos, music, and other files you control—to an external SSD.

This is often a more appropriate way to free internal storage than attempting to delete files that macOS manages as System Data.

You should aim to have 15-20% of your total internal storage as free space (~30-40 GB as an absolute minimum). If you do not have enough free space on your Mac’s internal storage, then here are some steps to take to safely free up space:

Free up storage space on Mac - Apple Support

Optimize storage space on your Mac - Apple Support

How to free up ‘System Data’ and other st… - Apple Community

"System Data" comprises your data, but they are typically hidden files that Spotlight cannot assign to a specific category like Documents or Applications. Examples include Outlook attachments, iOS updates, Cloud storage caches, etc. Starting with macOS 27 Golden Gate, System Data also includes what macOS used to call ‘purgeable’ storage – system caches, Time Machine snapshots and some other data, though the user had no control over the purging. Trying to manually clean out hidden files in System Data is likely to cause more problems than it solves, macOS hides those files for a good reason. Follow the steps in the linked articles above. 

You can check the amount of free space you have on your Mac in a variety of ways:

• Select your internal drive then click File menu > Get Info, check Available space
• Go to System Settings > General > Storage, check the graphical display at the top of the settings pane
• In Disk Utility (in Applications > Utilities), by selecting the main container disk below the drive itself (you may need to select View menu > Show all devices to see it)
• In the System Report – hold the Option key and click the Apple menu > System Information (the top menu item), look for the name of your internal drive (Macintosh HD, unless you have renamed it as I did)

On Tahoe, use one of the last two options, the first two show 'available' space which is not the same as free.

More detail on this change in this User Tip:

System Data and Free Space Changes in Gol… - Apple Community

The best advice is to just ignore the System Data category. ‘System Data’ is merely a catch-all category for files that Spotlight cannot assign to specific categories like Applications, Documents, Photos, etc. In fact, what is now shown as System Data used to be reported as ‘Other’, Apple changed the label in macOS 12 Monterey. System Data probably sounds better, but Other was closer to reality.