My wifes macbook didn't start anymore, it tried but went into the same error again and again. This is how I got the data from the old hard drive.
Get yourself a drive to rescue the files to (we will call it
LIFEBOAT). Connect it to the mac.
Enter Recovery mode by pressing
Get yourself a terminal (in the upper menu under "Utilities").
LIFEBOATcan be found under
Make sure your userdata is in
Copy the files you need to the
LIFEBOATwith a simple
Close the Terminal (
CMD-Q) and shut down the Mac.
The critical step is clearly step 5. If the data is not there, I have no idea what to do.
The mac I used was running an old version of OSX (Mavericks) and I think in the newer ones the files might be encrypted.
I did have two backup plans:
Try to find whatever is left from the files with TestDisk, perhaps after copying the drive to make sure I don't destroy anything by excident. This was a recommendation of Pascal and David.
Pay someone to rescue as much data as possible. There are companies for this.
In the end I was very glad to get everything back.