'Erase Free Space' on Yosemite getting 'Couldn't create temporary file' error.

I also cannot use disk utility to secure erase free space. The error message says the system "couldn't create temporary file." I saw another problem entry similar to this with a response to securely erase the whole volume and restore from the backup. While this might work, it doesn't answer why this error is happening, and it is something of a 'nuclear option'. Is there a better solution that solves the issue?

Yosemite 10.10.3

iMac (24-in, early 2009)

3.06 GHz Intel Core 2 Duo

4 GB RAM

640 GB WDC WD6400AAKS-40H2B0 Media fixed disk

I have the exact same problem. Has anyone found a solution yet?

Yosemite 10.10.4

iMac (21", late-2013)

2.7 GhZ Intel Core i5

8GB RAM

1TB memory

This was happening to me also when trying to "erase free space" while logged into the operating system. You need to shut your computer down, then hold/press command + r while the computer is loading before it gets to the desktop. This will take you to the recovery console. From there you run the disk utility and choose erase free space and it will work without the error.

Has anyone else tried Papadonkey's suggestion and did it work?

Doesn't work. The option to erase free space is grayed out when you boot into recovery mode. You can erase the disk, but not erase only the free space.

It wasn't grayed out for me. It did work for me. Not sure why the button is grayed out for you. Maybe you have a solid state drive?

I do have a SSD.

I did finally get my free space erased. I found also that I could not verify/repair permissions or verify/repair the drive. I don't know what finally made it work. I went into recovery mode two different times and verified & repaired the drive (no problems were found in any of these processes). Then I restarted and was able to repair permissions then erase the free space.

It an Apple Support Article OS X: About Disk Utility's erase free space feature - Apple Support it says "Note: With an SSD drive, Secure Erase and Erasing Free Space are not available in Disk Utility. These options are not needed for an SSD drive because a standard erase makes it difficult to recover data from an SSD."

Heres some more info about erasing an SSD drive. http://osxdaily.com/2013/04/22/secure-erase-mac-ssd-drive-recovery-mode/

Thanks Badunit and Papadonkey. I am afraid of going into recovery mode and never coming out again! Can you tell me, when you boot up the recovery console, do you automatically see the Disk Utility or do I have to issue some command to get to it? And, when I am all done erasing my free space (assuming it works), how do I exit the recovery console? Thx!

Booting with Cmd+R brings up a menu of things you can do. One of them is Disk Utility. Click on it. After using Disk Utility, shut down or restart just like you normally would and it will boot up normally.