0KB of disk space available, even after deleting files

[Wednesday, March 5th]

MacFixIt reader Bob Dodds recently described a significant issue, experienced by a number of users, in which various applications including the Finder report that 0KB of disk space is available despite attempts to delete files.

Bob writes:

"I have a iBook G4 1.33 ghz  running Mac oS X OS 10.4.11. I needed to free up space on the drive but no matter how much I delete it still says OKB available and I can't save things to disc. I've deleted over 2GB of files and verified and repaired permissions it with disc utility. It says the drive is OK."

The first step in countering this problem is to find out what exactly is eating your disk space. We've documented the usage of a utility called WhatSize that provides you with a hierarchical listing of all the directories and files on the selected volume, organized by descending size. This makes it extremely easy to navigate through the largest folders and look for the largest files within those folders, quickly running through the entire list and plucking items that you find useless or are willing to erase to reclaim disk space. Items are even color coded; those above 1 MB in purple, those above 1 GB in red, etc.

Alternatively, fire up the Terminal (located in /Applications/Utilities and run the following command:

• sudo du -h -d 1 /

This will show you disk usage for all files (including invisible items) on the root level of your startup drive. If something looks like it's taking up more space than it should be, investigate by navigating to the questionable directory using the cd command (type man cd in the terminal for usage instructions) and then running the command sudo du -h -d again (this time without the trailing slash). Use the rm (type man rm in the Terminal for usage instructions) command to delete unnecessary files (do not delete files you don't recognize).

Unfortunatley, knowing what's occupying your disk space is only half the battle. If you're deleting files aggressively and still getting 0KB disk space error messages, some application or process is likely spawning files that consume disk space. After you've used the above method to identify the space eater(s), try to associate it with a specific application. Quit that application if it's open, or use Activity Monitor (located in /Applications/Utilities) to force-quit its process. You can also inspect log files with Console.app (also located in /Applications/Utilities for processes that are persistently writing files or expanding extant files.

Finally, the fs_usage command can be useful in monitoring write activity to your disk. Launch the Terminal and type sudo fs_usage then watch as items scroll by. Processes names appear in the far right, and directly preceding them, a "W" will appear when a write process is occurring. If you see a third-party application suspiciously writing lots of data, investigate further.

Feedback? Late-breakers@macfixit.com.

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