Solve OS X Prohibited Sign Boot Issue

Recently, I used my MacBook Pro to the end of its battery life and closed it shortly before the battery died. Something must have gone wrong there because when charging and awaking it, the touchpad ceased to work and logon didn’t work. Thus I cold rebooted it and was greeted by a nasty prohibited sign.

OS X Prohibited Sign

Unfortunately, Apple’s own recommendations did not solve the issue, so here is my solution:

Boot into the recovery partition by holding cmd+R at startup and open the terminal.

For me this looked like:

start size index contents
0 1 PMBR
1 1 Pri GPT header
2 32 Pri GPT table
34 409606
916770904 1269536 2 GPT part - 48465300-0000-11AA-AA11-00306543ECAC
918040440 136
918040576 59064320 3 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
977104896 131
977105027 32 Sec GPT table
977105059 1 Sec GPT header

Apparently the GUID partition table got corrupted at index 1.

To fix this, first unmount the disk:

Remove the corrupt entry:

unmount the disk again:

If the partition was a normal HFS+ partition:

or for an encrypted partition as mine:

Now your partition table should be fixed. In disk utility, unlock your drive if its encrypted. Then repair the volumes and access rights as usual. For me disk utility still complains about a missing EFI Partition, but this is likely due to my refind boot loader.


After this procedure my recovery partition showed up on my desktop, you can hide it again with:

Dual Boot Ubuntu 14.04 LTS on Macbook Pro with Filevault 2

Although, I prefer working on Mac OSX or using a virtual machine for all my Linux needs, sometimes that just won’t cut it. Especially when working with ROS, a native Ubuntu can help.

Shrink some partition to make space in Mac Disk Utility
Download refind 0.8.1 and unzip
Install refind into the Recovery Partition

Mount the EFI partition and edit refind.conf. Uncomment the line with dont_scan_volumes but leave the parameters empty, otherwise refind wont find your original OSX boot Partition:

If something doesn’t work, don’t worry, you can still boot OSX by holding the option key at startup.

Now follow these instructions to create a bootable Ubuntu USB Stick. Load it with the refind bootloader and select „Try Ubuntu“. Open a terminal and start the installation without boot-loader:

In the installer choose installation type „Something else“, select the free space created at step one, format as ext4 and mount at /.

Now you should have a working dual boot configuration.