10.9.3 update may create hybrid GPT/MBR partitioned disk

[RehabMan]

Just a little warning...

On my 4540s, I have Clover-based pure GPT install dualboot Win81/OS X setup. In this scenario, the drive is partitioned pure GPT (no hybrid).

It seems that the 10.9.3 created a hybrid GPT/MBR partition scheme during the update process (Mac App Store based update). Of course, this broke Win81 boot as it expects pure GPT for UEFI. Solution: boot into Linux and "nudge" a partition such that gparted creates a pure GPT partition table.

 

[antonioj07]

What happens for people using Chameleon? I also have dual boot with Windows 8.1

 

[RehabMan]

What happens for people using Chameleon? I also have dual boot with Windows 8.1

For those using Chameleon, you already have a GPT/MBR hybrid, so no issue. This issue will be specific to Clover dual-boot scenarios where Windows is installed UEFI.

 

[imade]

Just a little warning...

On my 4540s, I have Clover-based pure GPT install dualboot Win81/OS X setup. In this scenario, the drive is partitioned pure GPT (no hybrid).

It seems that the 10.9.3 created a hybrid GPT/MBR partition scheme during the update process (Mac App Store based update). Of course, this broke Win81 boot as it expects pure GPT for UEFI. Solution: boot into Linux and "nudge" a partition such that gparted creates a pure GPT partition table.

Thanks for the heads up RM. I'm using a non-clover setup on my machine.
It would be great if some one documents the procedure to safely update the machine.

 

[RehabMan]

Thanks for the heads up RM. I'm using a non-clover setup on my machine.
It would be great if some one documents the procedure to safely update the machine.

Already done. See sticky guide.

 

[nguyenmac]

I don't have this problem.

 

[RehabMan]

I don't have this problem.

Just saying I did, so watch out, and realize the solution is simple...

 

[schinkengott]

i also got no problems.

 

[anirudhramnath]

I have non-clover installed. Updated to 10.9.3 using RM's sticky. No problems at all.

 

[RehabMan]

Note that my update on this machine was a bit rocky...

I allowed it to "Update All" (iTunes update + 10.9.3). First boot through, iTunes failed to "validate", so it didn't do anything. Second update attempt was 10.9.3. It rebooted twice. Once after the normal update process and a second time into what looked like the OS X installer! Finally it rebooted back into OS X with 10.9.3 and I was able to install the iTunes update. I think somewhere in that second OS X installer process was where it decided to "fix" my partition table (after all, real Macs need a hybrid for Windows, as real Macs don't support Windows in UEFI).

My Lenovo u430... same config (Windows UEFI, pure GPT, Clover)... didn't have this issue.

I'm about to see what happens with my 4530s. Edit: No problem on the 4530s. I did not apply iTunes update at the same time as the 10.9.3, so maybe that was the difference.