Error installing High Sierra from Mountain lion

Hello,

I am working on updating a 15" macbook pro. Currently it is running OSX 10.8, Mountain lion. I successfully downloaded the "High Sierra" upgrade from the appstore and ran it all the way to asking permission to install on the disk. However, when I click "Install" I get an error reading:

"An internal error occurred while preflighting your volume for APFS conversion."

I'm not sure what to do about this. I've tried PRAM reset and disk permissions repair.

Thanks