A MacBook Pro whose startup disk is almost full has a soldered SSD that starts at 512 GB on the base 14-inch and reaches 4 TB (8 TB on the M3 Max), per Apple's tech specs, but a Pro user's projects fill it fast: video, audio libraries, virtual machines and caches. Apple's storage article gives the order: open System Settings, General, Storage, see what is largest, move or delete files, empty the Trash, delete apps you no longer use and turn on the storage recommendations. System Data (or Other) is Apple's catch-all category. On a Pro the SD card slot and three Thunderbolt ports make an external SSD an easy overflow.
Differential
Likely causes of “Apple MacBook Pro 14-inch and 16-inch storage is full or nearly full”, and how to tell them apart
- 1
Project files and media
What separates it Movies, Documents or Music Creation dominate the Storage bar
How to confirm Apple lists Music Creation, Documents and TV among the categories to review; move finished projects to an external drive
- 2
Apps and virtual machines
What separates it The Applications category shows many large items that you rarely open
How to confirm Apple says to delete or uninstall apps you no longer use
- 3
Mail attachments and messages
What separates it Mail or Messages shows gigabytes of attachments and old conversations
How to confirm Apple's article lists Erase Junk Mail and Erase Deleted Items in Mail and the Messages category
- 4
System Data growth
What separates it System Data is large and unexplained and keeps growing between checks
How to confirm Apple describes it as a general category; a restart and clearing caches shrink some of it
- 5
No room for an update
What separates it Software Update says it cannot install for lack of space
How to confirm Free space first, then update; Apple's update article names storage as a cause
Before you touch a setting
Record this first — changing settings destroys the evidence
- Which MacBook Pro you have and its SSD size (512 GB to 8 TB)
- The largest categories under System Settings, General, Storage
- Whether iCloud storage optimization is on and how much iCloud space remains
Try in this order
0 of 7 completedSee the breakdown
ReversibleOpen System Settings, General, Storage and click the information button beside a category to see the options for that category.
Empty the Trash
ReversibleApple says a file moved to the Trash keeps its space until you empty the Trash.
Move finished projects off
ReversibleCopy media and project folders to an external SSD on a Thunderbolt port, check they open, then delete the originals.
Remove unused apps
ReversibleUninstall apps you no longer use from the Applications list, starting with the largest, to free the most space quickly.
Use the recommendations
ReversibleTurn on the Storage recommendations you want, such as storing files in iCloud, so macOS moves older files off the disk for you.
Clean up Mail and Messages
ReversibleIn Mail use Mailbox, Erase Junk Mail and Erase Deleted Items, and review large message attachments that take up space.
Restart and recheck
ReversibleRestart, then open Storage again and confirm that the free figure has risen as you expected before trying the update.
Model-specific
What is true of this model and not of its siblings
- Storage by model
- 14-inch M4: 512 GB or 1 TB. M4 Pro and Max: 512 GB to 4 TB. M3 Pro and Max: 512 GB to 4 TB, and 8 TB on the M3 Max. Per Apple's tech specs.
- Overflow options
- SDXC card slot and three Thunderbolt (USB-C) ports on every model in this family.
- Part numbers
- No part number is involved. The SSD is part of the logic board, identified by model and serial number.
- Tools and supplies
- An external SSD with a USB-C cable, the Storage screen and a dry towel for the desk. The Pro should not be opened at home.
- Repair cost
- Storage cannot be upgraded. iFixit's table lists Apple's US estimate for a MacBook Pro battery at $249; a full-disk fault is solved by clearing files, not a repair.
- Other models this page answers
- These steps also fit the MacBook Pro 16-inch (M4 family), MacBook Pro 14-inch (M3 family).
Stop boundary
When this stops being a self-service repair
- !If System Data stays large after a cleanup and a restart, contact Apple before deleting anything else
- !If iCloud will not sync, check your iCloud plan and Wi-Fi before deleting local files
- !If you keep running out of space, plan an external SSD or a larger iCloud plan, since the SSD cannot be upgraded
Evidence ledger
Sources behind this answer
Checking storage, moving and deleting files, System Data, iCloud optimization and temporary space.
Free disk space as a cause of slowness.
72.4-watt-hour battery, three Thunderbolt 4 ports, 24 hours video, Center Stage camera and display support.
100-watt-hour battery, 140W adapter, Thunderbolt 5, HDMI, SDXC and ProMotion.
Apple silicon MacBook Pro history: 14-inch and 16-inch generations, ports, displays and fans.
Exact questions
Common questions
Should I use the SD slot as extra storage?+
An SDXC card is fine for archives and camera imports, but it is slower than the internal SSD. Keep active projects on the SSD or a Thunderbolt drive.
How big is the Pro's SSD?+
Apple lists 512 GB or 1 TB on the 14-inch M4, 512 GB to 4 TB on the M4 Pro and Max, and 512 GB to 4 TB (8 TB on the M3 Max) on the M3 Pro and Max.
Which external drive is best?+
A Thunderbolt or USB4 SSD on one of the Pro's three ports is fast enough for most projects; Apple lists Thunderbolt 4 at up to 40Gb/s and Thunderbolt 5 up to 120Gb/s on the Pro and Max.
Why did the Pro lose space after an update?+
macOS keeps temporary installer files and may reindex. Apple's article describes temporary space that is freed later.