Can’t increase partition size of cloned volume in Mac OS X 10.11 (El Capitan) I have a MacBook with a 120 GB SSD. I bought a new one with 240 GB. I cloned the content from the old one over with an ICY BOX cloning device. I inserted new SSD in the MacBook and everything is fine and works. But I then noticed in the disk utility that the size of the partition is still the old one (120 GB).

So here is what I have tried so far:


I dragged the partition in the pie chart to use all unlocated available space. But then I get the error from MediaKit: "Error: -5341: MediaKit reports partition (map) too small".
I ran GParted on a USB flash drive, mounted it and gparted noticed some errors with the partition. it immediatly repaired it. Then I tried to increase the partition within GParted. But this was not possible. GParted can't increase HFS+ format. But after repairing it with GParted, disk utility does not show free space any longer.

I ran Terminal and diskutil resizeVolume. But it breaks up with an error message: "Error obtaining partition map size information"



And now I am completely lost. What’s wrong and what can I do to reclaim the additional space?
In general, when you use those hardware-only cloning devices—like that ICY BOX you mention—you end up in situations like this. Perhaps there is a cleaner way to recover from a situation like this, but in my experience what you are attempting to do just won’t work; hardware cloning like that is strictly one-to-one as far as volume size goes. And if the target volume size is larger than the source size, the situation that you are in happens; the volume is cloned but the maximum destination volume size becomes exactly the same as the source volume size.

What I always do for cases like this—cloning smaller drive to larger drive—is to hook up the new drive to the machine in some way (such as an external USB enclosure) and then clone it via rsync or Carbon Copy Cloner. This strictly copies OS level data from one device to another; not partition data/info so this always works right off the bat.