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I am creating a trial version of my application.

The trial should run for a maximum of 3 days.

Recently I came to understand that it isn't that simple. As I tried to use system date to count 3 days but the user changes the current date to a past day so it increases the trial period. So, anyone can suggest how to maintain 3 days trial?

Software Development Platform : Visual Studio 2008

Language : C# (Windows Form)

Stephen Kennedy
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Developer Nation
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    possible duplicate of [Create an application that will expire after a trial period](http://stackoverflow.com/questions/1417848/create-an-application-that-will-expire-after-a-trial-period) and many more http://stackoverflow.com/search?q=%5Bc%23%5D+trial+limit – Alex K. Jul 22 '15 at 12:09
  • @AlexK. you can say that it is duplicate but my way around is to use system date and i have searched the internet and cant find a possible solution for it. – Developer Nation Jul 22 '15 at 12:12
  • As you have discovered using the system date is a poor choice and there is no reliable way to deal with the user changing it, a conclusion that is repeated in the dups. – Alex K. Jul 22 '15 at 12:14

1 Answers1

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you may try :

save the start date. if the start date is HIGHER than current time -> exit

or you may switch to : count the minutes the program running. over 600 ->exit (or 800 or 900)

or you may get the time from internet, not local :

http://www.timeapi.org/utc/now

Chaka
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    Alternatively you could save all dates at which the programm has been started. As soon as you'd add the 4th date -> exit. So if a user tries to set back the system time, it would cost him a day :-) – LInsoDeTeh Jul 22 '15 at 12:21
  • @LInsoDeTeh, This not work if user change date to the original(first start) every time he starts application – Fabio Jul 22 '15 at 13:21