System Data memory demand

Hi there

further to my last on Jan 10 I've been working through all the suggestions and after a long search I found a large file (319.34 Gb) in Macintosh HD /Library/Info that was set up 17 May when I bought my previous Macbook. Looking into it I found a folder of about half that size relating to Mobile Data backups. I deleted it - with no apparent problems so far - and now the overall storage is much better. I think I haven't finished yet and must do some more work, but just want to thank you very much for takingb the time and providing the information that has helped so much! Best wishes.

Thanks Sonicray! I worked through both links that you suggest. The first one works through fine but has made no apparent difference to the amount of System Data. I switched off the Time Machine as detailed, but this makes no obvious difference. I didn't try the other suggestion as you mention it's better tried with older OS.

This laptop is on Monterey 12.1 and currently shows 23.66Gb is available out of 512Gb storage. Of this 308.69 is allocated to System Data. The remaining 185.69 is made up (in order of size) by icloud storage, Apps, Docs, Music and Macos.

I think there is some (hidden) management of this, as the total amount doesn't seem to move above 495Gb of storage. Whenever I remove something from my own material - eg documents - there is no noticeable c hanged in space available, as the System Data seems to refill in proportion to whatever I remove. I wonder if anyone has a handle on how Monterey os working? Many thanks for your help - much appreciated!