System data is suddenly fiiling my iMac HD

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Level 1

9 points

System data is suddenly fiiling my iMac HD

My iMac Late 2017 / Mac OS Monterey 12.6 / 2TB Fusion Drive HD / 64GB RAM suddenly ran out of disc space a couple of weeks ago. Only 77MB disc space left, normally there should be about 1 TB free space.

"About this machine" tells me that the HD is filled with more than 1 TB "system data" (please excuse that the Screenshots are in Norwegian language since I am asking from Norway, and please excuse me sometimes lacking the best phrases to explain in english)

I have deleted some big files to regain comfortable free space on HD (now about 140 GB), but I need to find out what causes the HD to fill with "system data", stop the process, and finally find a way to get rid of it.

When I look into the System folder under Macintosh HD, the content is only 28,65 GB. So I ask myself, where is the rest?

Trying to resolve the problem I have tried to stop automatic Time Machine backup for a few minutes, following Apple's receipt to get rid of Local TM backups, which I have seen the user Tesserax suggest on a similar problem in this forum. About Time Machine local snapshots - Apple Support

No luck. (The backup disc has also been filled.)

I have also tried to boot in Safe mode, log off and then boot normally. Still no luck, nothing has changed.

Anyone here who knows what to try next?

Posted on Oct 11, 2022 11:46 AM

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Answer 1

Mal-S

Level 5

5,020 points

Oct 11, 2022 12:53 PM in response to tormeid

A few simple things to try before you do anything else.

Start up in Safe Mode followed by a normal restart
Force Time Machine to delete local snapshots by turning off Time Machine in System Preferences and when it has finished deleting the snapshots turn TM back on again.
It is good practice to shut the iMac off regularly.

As this question has be asked many times you will find further discussions on the subject by doing a search.

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Answer 2

tormeid Author

Level 1

9 points

Oct 11, 2022 1:42 PM in response to Mal-S

Thank you Mal-S for kind reply.

As I tried to explain in my question, I have already searched Discussions, and tried both Safe Mode and forced deletion of local TM snapshots, as I found these measures explained in earlier discussions. Tried both again now, but the situation remains the same.

The iMac is regularly turned off and the cord disconnected, 1-2 times/month while I am traveling.

Sorry to say, I still haven't found any explanations/solutions in Discussions which solves the case. But thanks a lot for your reply.

(I have also had a conversation with Apple support, but he didn't find a solution either. In our local Apple shop they suggested a theory about iCloud running wild, copying picture files without proper labelling onto the machine, looking like System data instead of ordinary files.)

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Answer 3

Oct 17, 2022 1:43 PM in response to tormeid

I have this problem and this question as well - my iMac (late 2015, Monterey) 2 TB HD contains 1.46 TB system data. I do not know what to do and need help urgently. Any suggestions beyond Safe mode, elimination of local snapshots ? Thank you...

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Answer 4

tormeid Author

Level 1

9 points

Oct 18, 2022 8:50 AM in response to anneliese49

Hi Anneliese49

I just resolved my problem. By pressing Uppercase-Cmd-Period (.) I found the User-Library folder, which appeared to contain 1.06 TB of data. By searcing the directory I found one single folder named "Screen recordings" which contained one single .mov-file 1 TB. By deleting that file, the data was gone and problem solved.

What obviously has happened is that one day, instead of taking a snapshot of the screen, I had errouneously started a screen recording. As I wasn't aware of it, the recording may have continued for hours and days until I got a warning about limited HD space left. The recording probably stopped when I disconnected from the internet in a panic attempt to stop any invisible downloading. Without access to the User>Library folder I wouldn't have been able to find and delete the big file which showed as "System data" in System preferences.

I hope this may be of some help for you.

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Answer 5

Oct 19, 2022 2:49 AM in response to tormeid

Thank you very much, Tormeid ! I immediately had a look at my UserLibrary folder, but no big files to be found there, helas.

Something else must be causing this "leakage" - if I find out, I will certainly let you know. I am glad that your problem at least is resolved. Regards.

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System data is suddenly fiiling my iMac HD

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