My Internal drive is not able to mount after decryption of FileVault

I'm using a MacbookPro 2007 Model running on OSX 10.10 with 2.8Ghz, 8GB RAM and 500 GB HDD.

It started when my already encryted Mac 'hung' when I couldn't login from the lock screen for some time. So I force it to shut down and causes long bootup time. Therefore I started in Recovery Mode hopefully to decrypt first my drive first so it wouldn't take a long time to boot. So from Recovery Mode, I used Disk Utility, select my drive and Unlock the drive first, then decrypt.

I followed the process by running {{diskutil coreStorage list}}. Upon completion, I tried restarting my Mac and I was puzzled because the encryption was still active (as I needed to enter the password upon turning it on) and a while later there is a screen like "Do Not Enter" symbol. I restarted in Recovery Mode and try to mount the drive in Disk Utility - didn't work.

I did it the Terminal way and some weird error came out.

Error: -69774: Couldn't bring the new Core Storage Logical Volume online

It seems that my Logical Volume is not assigned a Disk (or is that a behaviour when the disk is not mounter). Appreciate if anyone who has knowledge on this to help 🙂