Hello - When I try to sign up for an account and pay it tells me:
You need to add [Email address] from the Insync desktop app first before buying
Please advise.
@Thomas_Otte We didn’t think that it is logical for you to buy Insync without trying it first, so we didn’t allow this. Please download the app, https://www.insynchq.com and add your Google account to the Insync app. 
How to get started with Insync
Once added, you may go back to the buy page. 
https://www.insynchq.com/pricing
Thank you.
Ah ok so I have to wait until the trial is over to buy it, because I already added the account and it still doesn’t let me pay
Are you entering the same email in the buy page as you did on the Insync app?
Yes I am, or at least I think so.
Can you PM me your email so I can check?
I kept getting this error on my mac, to resolve it I had to uninstall the application, then delete the application support files in my library. Once I did this I was able to purchase your product. FYI in case anyone else runs into this.