Macbook 系统数据超过200G，尝试多种方法仍然无法删除，疑似keynote文件缓存过大

You are welcome 🇨🇦

There are two options as mentioned earlier

Moving Forwards so this does not happen again is a very good question 👍

System Data technically, has a mount point /System/Volume/Data 

With a mount point of /System , this Volume is part of the Operating System and can not be deleted - full stop

It is where your User Account (s)  was made when the computer was First Setup as New

We can point-out what may be included in this Volume

Though, how to reduce this is a long and complicated trial and error process

The category is a collection of files which include:

• System temporary files

• macOS system folders

• Archives and disk images (.zip, .iso, etc. - often found in the Downloads folder)

• Personal user data

• Files from the user’s library (Application Support, iCloud files, screensavers, etc.)

• Cache files

• Fonts, plugins, extensions

• Other files that are not recognized by a Spotlight search

• Media files that cannot be classified by Spotlight as a media file because they are located inside of a package

•Time Machine Backup Snapshots that have not been transferred to the TM Backup Drive 

• Locate backups of your iPhone, iPad, and iPod touch.

•Was there or is there another user account currently or previous used on this computer ?

Has the account been removed ?

Did the removed user account ’s Home Folder also been removed ?

Delete a user or group on Mac

• If using a Cloud Based Services to sync files,  like iCloud and One Drive. These can also occupy space on the Internal Drive 

They can be located anywhere on your hard drive. The files that you have control over are located in the Documents, Downloads, Pictures, Music and Movies folders.  You can use either of these two free apps, GrandPerspective , to find the largest files on your drive so you can determine if they can be deleted or moved to an external HD for storage.  

Another Application to find and analyze what is using space on the drive is Etrecheck >> Clean up

2、采用柠檬、cleanmymac等第三方工具清理——无效

Any Third Party Applications that will interfere with the normal operation of the OS,  is an invitation for disaster. 

Certain Applications maybe available on the Apple Apps Store - this only means the Developer is prepared to pay Apple a percentage on each sale. 

What the Application may do to the computer is up to the User to check this out before purchase

Any of the below should be removed as per Developers Instructions 

Disk Cleaner 

CleanMyMac , aka “ BrickMyMac “

New macOS Malware "Cthulhu Stealer" Targets Apple Users' Data

Un-Like Microsoft Windows, which does have “ Disk Cleanup “ and “ Defrag “ as part of their Operating System 

Apple does not  

There are two different thought about how to handle a computer one this software is used on the computer

1 - Remove it

2 - Start Over from Scratch

For Apple Silicon computer >> Use Disk Utility to erase a Mac with Apple silicon.

This will action will not touch the operating system

Always make a Time Machine Backup  before  proceeding 

I would suggest Only Migrating the User Account and nothing more.