Huge System Data and Documents files filling up 1TB HD....

I have an M1 Mac Mini from which I need to move the contents as I am upgrading to an M2 Mac Studio. I was going to ask the community the best way to do this (just double-checking that Apple's Migration Assistant was the best route), when I realised I've got a different issue.


I have a 1TB SSD HD on my Mini but barely any files on the desktop – approx 30GB worth. I know I have all my photos and videos in the Photos app on my HD and they take up approx 150GB and approx 100GB Apps but looking in Sys Settings > General > Storage I can see there are the following:


200GB Documents

95GB iOS files

272GB System Data


I use Time Machine, BackBlaze and SuperDuper! for backups. I am guessing some of the above are from one or all of these. Does anyone know how I can purge or delete any of these before I migrate to my new computer so it's not full of files which may not be needed or actually be understood by my new machine?


In addition, if I am backing up mine and my family's iPhones to a paid fro iCloud, can I get rid of the iOS files?


Thanks

Mac mini (M1, 2020)

Posted on Nov 27, 2023 6:07 AM

Reply
8 replies

Nov 27, 2023 7:13 PM in response to Justanothergeordie

Anything listed as System Data will not be migrated. Since those categories are generated by Spotlight, and System Data is the catch-all for things it cannot put into the other categories, some of that could be your data.

You can delete the old iOS backups if you are backing up to iCloud. Locate backups of your iPhone, iPad, and iPod touch - Apple Support


Nov 27, 2023 11:02 AM in response to Justanothergeordie

The generally recommended way is to have a current Time Machine backup of the old Mac and connect it to the new Mac before starting the initial setup. During the setup select the option to use Migration Assistant and the Time Machine update to migrate your user data.


Do not use WiFi as it's so very slow compared to direct cable connection and could be vulnerable to interruptions.


Nov 28, 2023 6:48 AM in response to Barney-15E

Amazing, thanks. So from my original question am I right in thinking:


– As long as all my family's phones are backed up to iCloud+ then I can delete the old iOS backups using your link


– If I take Old Toad's advice and migrate using a Time Machine backup it will be quicker than using WiFi but might this include the System Data you say won't be migrated?


Thanks

Nov 28, 2023 1:16 PM in response to Justanothergeordie

For the first one, yes.

For the second question, system data is not a standalone category. There are specific file types that are definitely system data. But system data is a catch all for items. Spotlight couldn’t categorize as documents or applications or the other categories. So, when you migrate, some of what is listed as system data could possibly be migrated because it’s not system files but is your data being mischaracterized by Spotlight.

Dec 4, 2023 11:01 AM in response to Barney-15E

I migrated over to the M2 over the weekend and all went smoothly apart from some software still being incompatible with Sonoma but that's fine.


As a test I kept my M1 Mini to one side with all my files on it and then started using the M2 Max today but didn't set up Time Machine or BackBlaze. Available storage has gone up from approx 199GB to 369GB.


Of this System Data has gone from 272GB to 101GB. iOS Files from 95GB to 79GB. Documents is pretty much the same. So it looks like it was TM and BackBlaze snapshots...

Huge System Data and Documents files filling up 1TB HD....

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