System is taking up too much flash storage on my MacBook Air

Hi,

The storage reporter is too often wrong. System should not take up 40GBs.

Rebuilding the Spotlight index may help it: https://support.apple.com/en-us/HT201716

If not, click once on your HD icon on the desktop > go to File menu > select Get Info > what does it say for Capacity and Available?

If Available really is too low, it's time to transfer or delete some data, as you don't want your startup volume to get below about 10GBs of available space.

First, backup in case you deleted something you wish you hadn't. Then use one or more of the following to see exactly where your space is being used, then transfer/delete larger files until you increase the available space to about 10GBs and that will do for now; do not transfer/delete anything unless you're sure of what it is, and not something the OS needs:

https://www.omnigroup.com/more (OmniDiskSweeper)

http://grandperspectiv.sourceforge.net (Grand Perspective)

http://www.derlien.com/downloads/ (Disk Inventory X)

Goldname wrote:

On my Macbook Pro, the System storage is also about 40 GB. How can they both be wrong?

I've seen stranger things, but that is definitely odd. Are both running 10.12.4 by any chance?

Should the System storages be different on different computers despite the same operating system?

I don't know the answer to that for sure, but I just checked two different machines of mine, both running El Capitan (not Sierra) and with everything installed on them the same, and the storage reporter doesn't show System in El Capitan, but for all the other categories, the numbers are almost exactly the same, so that does show that it should be the same between different machines.

Which leads us back to why System is taking up 40GBs. It seems System on Sierra includes other things.

See the following thread for a number of things which worked for different people. It's rather long, but if you want to get to the bottom of this, try out the "fixes" until one works for you. Probably the easiest, which you can try right away, is to boot into Safe Mode and back again: https://support.apple.com/en-us/HT201262

Please post back if something works for you.

'System' as listed in the About this Mac report is worthless.

It is a combined from Spotlight index data. You are assuming that 'System' means only the OS's files, that is not the case. 'System' in that report is a vague term that also covers data outside the '/System' folder e.g. file version data that will vary on each OS.

You can't compare that figure unless you have actually used each Mac exactly the same. In general the /System folder will be similar sizes on each Mac but logs & caches can make a difference. You need to avoid deleting (or attempting to delete) files in /System.

Ignore the report & use the actual free space in the Finder as a guide. OmniDiskSweeper & the other disk size apps will use the file size calculations & ignore the Spotlight index.

Bear in mind that you cannot see the size of folders that you do not have permission to read - if you cannot find all your used space post back here. There is a technique in the third party applications that reveals it.

I don't remember if every storage report issue I've seen has been on 10.12.4, but I know I've seen a lot of them with it....