No disc space and huge System Data = really need some help

You need to also know that when your DD becomes to full, your computer can stop functioning and then you have a serious issue. When you run out of space on your HD you will need to install an external disk. Then you can transfer files, such as photos or music files to the external disk and that will allow you to delete them from your HD to clear up the needed storage space. These days these disks are cost effective, compact, easy to install with vendor provided USB cables and most do not require external power. You may have to reformat it though. There is a large selection of disks to choose from. This solution will allow you to easily have the storage you need.

Adrian Collins2 wrote:

I have a MacBook Pro (14-inch 2021 M1 Pro) running Tahoe 26.1. My free disk space was very low (ca. 1.5gb) and I researched and checked settings to Optimise storage. System Data is about 181GB of 500GB drive. I have 2 user accounts (personal and work). I have iCloud, OneDrive and Dropbox offline storage - all set to download on demand/only keep recently used files on HDD. Deleted my last TimeMachine (saved to QNAP drive).

Now have no disc space left and can't load apps? Any assistance greatly appreciated...

ref: Free up storage space on Mac - Apple Support

You can see the big picture selecting the Macintosh HD and Command i opens the Information pane...

further—

Call Customer Support (800) MY–APPLE (800–692–7753)

or on line https://getsupport.apple.com/

Outside the USA—Contact Apple for support and service by phone

See a list of Apple phone numbers around the world.

Contact Apple Support - Apple Support