@Anonymous
Welcome to the Autodesk User's Community..
From what I'm reading it looks like you were. But let's go over a few things since there are so many things not adding up here and it doers raise so many red flags in my opinion...
Not sure where you're located.. But if you reside in the USA you are not allowed to make purchases like this of legacy Autodesk software. Overseas the rules are little more relax and permitted. If the seller was located in the USA they are not permitted to sell it either.
Software installation is just software installation.. It doesn't matter if you were installing the student or commercial version. When you go to activate it, then it determines what type of license it is. So the actually software media you have is okay but the activation is the problem since it activated as a student version.
Student versions are only allowed for those who are currently signed up and attending a qualified educational institution. https://knowledge.autodesk.com/customer-service/account-management/education-program/who-can-join/el... The activation/license is only good for 3 years. Once it expires it can't be reactivated. In addition anything used with a student license can only be used for learning and training while you attend a qualified educational institution.
In 2014/2015 Autodesk removed the Educational watermark, but in the 2019 release it came back. It is stated wither true or not, any Autodesk files created with a student version contains an internal educational watermark and if that file is used outside of training, shared and etc, well numerous individuals could be impacted and fined by Autodesk.
At the end of Jan 2016 (meaning AutoCAD 2017 wasn't out then), Autodesk stop selling perpetual license of single Autodesk product. So when 2017 was released all new purchases had to be subscription based. So the only way this 2017 license is perpetual is that it is truly a student version that will expire shortly (not in 3 years since you activated it) or its owner is listed as someone else or as a company. When it gets into ownership you could run into numerous legal issues.
When a student version is requested or when the serial # is issued to the student, the clock starts then and will expire in 3 years from that point. So my guess is.. The 3 yr free license clock has been ticking and will run out shortly. As of April 2020, the 2017 version will be retired and no longer supported by Autodesk.
Final thing.. If the serial # provided to you was a student version then the person who sold it no matter where they are located has no right to do that since they obtained it free in the first place. However I don't know the seller or where they got this from and etc.
In the end its not worth it.. Why risk the chance of being fined to save a few bucks. Its great that you want to learn AutoCAD or use it but at what cost.
Mark Lancaster
& Autodesk Services MarketPlace Provider
Autodesk Inventor Certified Professional & not an Autodesk Employee
Likes is much appreciated if the information I have shared is helpful to you and/or others
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