AOrlandini wrote:
• Sure, emptying the trash very often... sigh.
You don't need any 3rd party security apps on a Mac.
However, that has nothing to do with your storage problems.
The first thing to know is that this actually doesn't have anything to do with "System Data". I know it says that. It's totally lying to you.
It is better to think of this as "Other" data. I can't tell you what that other data might be. It's a recursive definition. "other" data is any data that can't otherwise be categorized. The only way I can make this more confusing is to call "other" data something that it isn't, like "system" data.
The operating system tries to categorize all of your data. So it groups things into "Moves", "Pictures", "Documents", "Apps", etc. But for anything that doesn't fall into one of those recognizable groups, it calls "System Data". And it's wrong.
What you have to do is use one of those storage management tools to find where this storage is being used. Since you've already installed EtreCheckPro, you have one, built right into EtreCheckPro. Go to the Tools menu and choose "Storage...". You will have to give EtreCheckPro Full Disk Access for this. That would be true of any such storage tool.
The EtreCheckPro Storage tool will show you a pie graph of how your storage is physically allocated on disk. You can click on each pie piece and drill down into the folders that are consuming the indicated amount of storage. You should eventually find some folder that has way too much storage being used.
Just be careful. You should really only delete files that you created. If you try to delete any other files, there is a risk of unrecoverable data loss. Be particularly wary of any "Library" folder. This is where apps like to store random stuff. Sometimes they go wild and write some log file out of control, or something. You can delete those files, but you might break some app that needs them. And that might have been an app you had important data in. And maybe the app syncs your file deletion with the cloud and deletes your data on all your devices.
This is why the EtreCheckPro Storage tools greys out these "Library" folders and disables the "Show in Finder" button. You can still drill down into them and see how the storage is allocated. But be careful!
Here is an example from the other day when someone used the EtreCheckPro Storage tool to find the cause of their storage problem: Full Storage on MacBook Pro - Apple Community
This is also a cautionary tale. I wasn't sure how to handle the storage in this case. I don't know if that problem ever got resolved. Such is life in the forums.
