Flashing question mark

supanatral

supanatral

Registered
I installed Linux on my mbp yesterday on an external hard disk but then after it finished installing, ir wouldn't boot off my internal solid state drive. I formatted my internal drive and installed mac again but I still get a question mark when I try and boot my computer.
 
Hold down the option key as the computer boots, and you should be presented with a menu of bootable media. Select your hard drive from the menu, and once successfully booted into Mac OS X, head on over to the "Startup Disk" pane in the System Preferences and ensure your hard drive is selected as the startup disk.

If your hard drive does not appear in the menu, that means that it's not a valid, bootable drive. You may need to reinstall again, ensuring that the drive is formatted as "Mac OS Extended (Journaled)" and that the partition scheme is, preferably, GUID, but can also be APM -- as long as it's not MBR (Master Boot Record).

Ideally, in order to make sure the Linux install didn't somehow muck with the partition(s) on your internal disk, you should perform a full repartition of the drive -- select "Partition" from within Disk Utility, select "1 Partition" (or whatever you prefer, as long as it's not "Current Partition Scheme"), and repartition the drive with the aforementioned settings (HFS+, Journaled, GUID).

When you installed Linux, did you also install some kind of bootloader, like Grub?
 
The drive doesn't show up when I hold option. I don't know if I installed the grub bootloader but if I had to guess, I'm pretty sure I did.

I reformatted the partition in disk utility and that didn't work. I also tried zero'ing out the disk. I didn't let it finish because I was just concerned about the beginning of the disk where the mbr was loaded but that didn't work. My next idea is to format it again and zero out the disk and let it finish.
 
I don't think zeroing out the partition will help with the "bootability" of a disk -- zeroing out a partition is more for security and error-checking.

I think you need to perform the actual repartition function I described above -- instead of just formatting the partition that's already there, repartitioning the disk will destroy all current partitions and create a new partition map on the drive. This is more likely to help with bootability issues than simply reformatting existing partitions, and if, in fact, you did install a bootloader, this will ensure that the bootloader is no longer present on the drive.

A repartition operation takes the same amount of time as a reformat operation -- I think your best bet to regain bootability on your internal drive is to repartition the drive and install a fresh copy of Mac OS X. Also, disconnect your Linux external drive during this process, just for safe measure. That will ensure that if the bootloader exists on the external drive, that it doesn't take precedence in the boot order after you clean install Mac OS X.
 
Ok-I'll try that when I get home tonight. I guess I'm
only zero'ing out the partition and not the disk. When I have this problem on a pc-I just run a utility that zeros the disk and it works but if it's only zeroing the partition then that makes sense why that didn't work. Thanks for your help. I'll be back later to report whether that worked or not.
 
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