My storage takes up more than 70 GB

Hi,

System can encompass a lot of different things, so it may be accurate.

However, the About This Mac > Storage report depends on the Spotlight index and may have a glitch, meaning it is too often not correct. Try rebuilding your Spotlight index, then restart: https://support.apple.com/en-us/HT201716

If no luck, try booting into Safe Mode: https://support.apple.com/en-us/HT201262 and check out the Storage report. It won't show categories (everything will show as Other), but should show accurate the amount of free space out of the total capacity.

Also go to Applications > Utilities > System Information > Hardware > Storage to see your total Capacity and space Available.

Click once on your HD icon on the desktop > go to File menu > select Get Info > note what it says about Capacity and Available.

These should be accurate.

To gain back some space, if you haven’t yet done so, backup in case you delete something you wish you hadn't. Then use one or more of the following to see exactly where your space is being used, then delete or transfer and then delete larger files (and empty the trash; you may also have to restart for the extra free space to show up) until you increase the available space to the desired level. 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)

I had the same problem. After updating I photo it duplicated all photos. With the new update I was able to delete the old iPhoto. It free up 43g. I also had a problem with keepin old phone backups deleting those helpe.