General Topics






Tips and How-To


Troubleshooting: kCantAllocateErr

Determining contiguous (unfragmented file system) free space...ERROR: can't allocate the required space [-40006], msg ="Cannot allocate minimum amount of contiguous free space (1GB)

This message arises with the recondition command. This is not a malfunction or bug.

Reconditioning requires enough unfragmented space to work efficiently; with too little unfragmented space the process might not work efficiently. In most cases, it indicates that the drive has been heavily used and/or is low on free space.

If the drive is over 90% full, performance might be suffering in other ways also.

Suggested workarounds

Make space on the drive

Usually there is ample junk on a drive to free up at least a few GB, which can sometimes be enough to create contiguous free space:

Clone and restore the drive

This approach has the added benefit of defragmenting the Mac OS X file system.

  1. Clone the drive to a backup (two backups strongly recommended!;
  2. Boot from one of the cloned drives;
  3. Erase the drive with Disk Utility, then recondition it;
  4. When done reconditioning, clone back to the original boot drive.
  5. Reboot on the original boot drive.

Note: making a clone of the boot drive on a regular basis is a good practice for backup purposes.