I purchased an MK3 secondhand on eBay

@dok.ryconn , check the below here, usually there is only a problem if the previous owner deny having sold the unit and thus denies a transfer of the hardware serial when N.I. looks into things or if the unit is of one of the "few exceptions with older products" mentioned in the reference below here

@Pippen , simply follow my guide below here :

Registering the hardware ought to give you the base software that came with the hardware (except maybe some legacy devices ?): Quote Matt_NI : All you need to know about License Transfer

All issues regarding serials and registration are handled exclusively by N.I. Account Support

Send support a picture of both serial on bottom of device and of your purchase receipt

The "resolution that works" is the click through make the right choices to open a ticket : N.I. Account Support

(You need to use browser with Cookie , Security and Extensions settings that will allow for log-in on the page for the page to work)

Scroll down to bottom of page N.I. Account Support and log in

Then click the Contact support

Then again scroll down and click the Contact N.I. support that shows

Then yes , damn it ! , then you have to click the Contact N.I. support again

1: Do you need help with the activation or installation of a product?

NO

2: Is your question about License Transfers / 2nd hand purchases?

YES

3: We have collected all info around 2nd hand purchases in this overview.

That doesn't help

4: OK. Are you a buyer or seller

Buyer

5 Have you received a License Transfer Token?

NO

6 Have you bought it from a shop (Guitar Center, Sweetwater, Thomann, etc.) or from a private person (Ebay, Facebook, etc.)?

Privately

7 Please ask the seller to request a License Transfer Token as explained in this article.

I Can't contact the seller

8 Please upload a photo of the invoice or receipt from the seller.

You have to take the rest from there yourself since I can not start opening empty tickets just to make a guide for you.