Cannot boot during Upgrade from Lion to El-Capitan

[ICEBreaker]

Hi fellow Mac OS X user,

I am running Lion (10.7.5) on a mid-2011 Mac mini which boots from an extended (journaled, encrypted) partition residing on a Crucial SSD. When I tried to upgrade to El-Capitan, the system could not boot during the installation process, and I was greeted with an icon of a folder with a question mark.

Searching online, I found out that systems with TRIM-enabled SSDs would not be able to boot after upgrading to Yosemite because of the implementation of Kernel Extension Signing. The problem is that I don't think this applies to me as I have never enabled TRIM. This is confirmed through the System Report which states that there is no TRIM support.

This leads me to think that perhaps it is related to the boot disk which is encrypted using FileVault. The booting sequence did not offer any opportunity to enter the FileVault password.

Is it TRIM related or encryption related? Does anyone know what I should do? Thank you in advance for any assistance or advice you can offer.

~ JC

 

[Fishrrman]

My suggestions:

First -- TURN OFF filevault for now. It could be "getting in the way".
Next -- use a bootable USB flash drive to install the OS.

To create the installer, use a flash drive 16gb or larger (might work on an 8gb, no promises).
Get ONE of the following:
- Boot Buddy (my favorite)
- DiskMaker X
- Install Disk Creator
(all are free)
- Initialize the flash drive to HFS+ and use one of the above apps to create the bootable installer on it.

Now... power down.
Insert flash drive
Reboot and IMMEDIATELY hold down option key and keep holding it down to invoke the startup manager.
Select the flash drive installer with the pointer and hit return.

When you get to the installer screen, "aim it" at the Crucial SSD and see what happens next.

 

[ICEBreaker]

My suggestions:
Next -- use a bootable USB flash drive to install the OS.

Hi Fishrrman!

Thank you for your response. Could you kindly elaborate more on why a bootable USB flash drive is required? I suppose I did not explain my predicament in more detail. The Mac has been restored back to its original state by using Time Machine, so there is no problem booting now. Otherwise I couldn't turn off File Vault even if I wanted to.

The issue that now remains is how to install El-Capitan. Do you still think a bootable USB is still required in this case or would it be fine to just run the upgrade again from the hard disk? Thanks.

~ JC

 

[Fishrrman]

"Could you kindly elaborate more on why a bootable USB flash drive is required?"

Just my preference.
If you haven't tried it, I suggest you do.