Target Disk Mode or TDM is an unique boot mode in Macintosh based systems that enables the drives of the targeted computer to behave as a FireWire mass storage devices. When a Mac that supports TDM, starts, it does not load the operating system but can be attached to the FireWire port of any other host system for formatting, partitioning or successful transfer of files. However, this process fails when you try to mount the hard drive volume of a system with an Intel-based Mac OS and the volume becomes inaccessible. This data loss situation does not have a safe solution other than any efficient Mac Data Recovery software to recover back your inaccessible data.

In the above instance of data inaccessibility, the error message reads as:

“You have inserted a disk containing no volumes that Mac OS X can read”


When you encounter the above error on your Intel based Mac OS X computer, mounting of the hard drive volume gets halted and you come across the inaccessibility issue. However, in Mac OS X 10.3.9 or earlier, when you connect an Intel based Mac OS X and start it in TDM, the hard drive might gets mounter and work as expected. The error dialog box consists of three options: Initialize, Ignore and Eject and you should opt for Eject or Ignore in order to dismiss the error box.


The drive that was started in TDM and could not be mounted, must have been formatted in a non Mac format, such as FAT32 or NTFS. The FAT32 or NTFS file format can not be read by Mac under Target Disk Mode.


In the above case, you need to format the Mac OS X hard drive in a Mac supported file format and use it as startup volume in order to connect it at a FireWire port. While under TDM, you need a Intel based Mac system as the host system to be connected to the target system and being formatted. In this arrangement, you can use Disk Utility to format and repartition the hard drive. However don't use a PowerPC-based Mac to format the disk as the Disk Utility will successfully format the disk but you will not be able to start the Intel-based Mac from it.

Formatting will resolve the problem for sure, but all your valuable data will be lost. Hence, these kind of data loss conditions require Data Recovery Mac to be be applied for safe recovery. Mac Data Recovery software are powerful applications that can recover your data from any such instance with ease. More over, they don't require any technical expertise to operate.

Source by Kuldeep Kulmi