Backoffice access denied and 500 error - failed migration to 1.7

[Amber123]

I tried to upgrade to 1.7 from 1.6 (big mistake) and then tried to reinstall a recent backup.

Now my website gives a 500 error, and the backoffice returns an access denied error.

I have a spinning puffin icon and a dropdown menu that doesn't load any pages.

I tried to change admin password and have changed the php version etc. Nothing has worked.

I'm afraid to start completely from scratch because I don't have the knowledge to manually migrate all my old product pages etc.

Any ideas?

[Amber123]

OK so apparently Hostgator (urgh) have a 500mb limit for cpanel restores.

I rang them and they took 30 minutes of international call time to tell me I had to use FTP to restore the website - real experts these guys. 

I managed to gain access to my FTP (FZ), apparently my entire email history is now deleted, and need to know how I restore my full website backup (tar.gz) via Filezilla.

I tried to drag across the zipped file - didn't work. I tried to drag an unzipped folder - didn't work. Website address just shows a directory. Backoffice doesn't exist 404.

I can't find a guid online. In hindsight, prestashop,  hostgator and me being a tech idiot was a rookie mistake. 

Help!

[Guest]

If you copied all the files from the backup to FTP, you must also upload the database backup for the old version of Prestashop.
The database for PrestaShop 1.7 will not work on PrestaShop 1.6 and vice versa will not work.