A computer repair customer of mine brought in a Macintosh Pro A1278 that would not boot into Macintosh operating system. This MACbook Pro would boot loop after displaying MAC logo and a progress indicator, only to display a blank screen. I decided to try to recover this customers' data just in case the hard drive is failing or the file system is corrupt.
I actually use Ubuntu Linux for data recovery service for MAC. Newer distributions of Linux do an excellent job of automatically mounting file systems including Macintosh Hierarchical File System. Hook up your hard drive to your recovery computer running linux and then boot like normal.
If the HFS file system and or hard drive is "healthy" enough then Linux should boot and automatically mount the file system for you. You can verify this at the command line by typing in fdisk -l. You will need root privileges in order to run this command.
root@b617:/home/user# fdisk -l
Another way to verify whether or not this file system was mounted is to open up file explorer and look for this hard drive. When I come across a failing hard drive or corrupt file system I get errors as soon as I log into the Linux Graphical User Interface. Once you have verified that this HFS file system was successfully mounted then you can browse these files.
You may need to login with the root account into a linux GUI if you get access denied permission problems on some or all files and folders. Now all you have to do is copy over files and folders to your local hard drive and or external media. Also, you can copy files and folders via command in a terminal window.
You may be presented with prompts for files that could not be copied. You might want to move these files or rename them and try again. As long as the hard drive is not physically failing or files are not corrupt, you should be able to recover your data.
Finally, I have been able to successfully recover data on failing hard drives with both Microsoft Windows and Macintosh file systems, using Linux. As a matter of fact, I have more success recovering data using Linux, then I do with using a Microsoft Windows computer, when it comes to recovering failing hard drives with Windows operating systems installed on them.