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I have created an Access application that I would like to make unusable after 7 days, much like a software provider’s free trial period. This would prevent my clients from stiffing me. Is this feasible?

I don’t know VBA.

Thank you very much in advance, Nathaniel

Mat Nadrofsky
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Nathaniel_613
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3 Answers3

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As Kevin Ross alluded to, calling back to an authentication server will be the most ironclad solution. It also creates a lot of other headaches, not the least of which is that the honest users tend to be put off by such a setup.

I think if you want to offer a trial version of your software, you should consider instead putting a hard limit on the number of records allowed in whatever your "main" table is.

I think this would be more effective for three reasons.

  1. It's harder to crack.
  2. Your users aren't under pressure. They don't have to try to figure out when they will have a week to devote to trying out a program. I often won't try a program with a limited time trial because I want to wait until I have time to really use it. But I never have that time to devote. So I never try the program.
  3. You can establish lock-in. If you make the number of records fairly large, your users could use your program for weeks or even months before bumping into the limit. By that time they may be depending on the program and feel they have no other option than to buy the full version.
mwolfe02
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There are a number of ways I can think of doing thing “in the box” i.e. without calling back to some kind of authentication server at your end.

The first one is when the application first launches it stores a record in a table that notes the date/time that the app was first launched. When the user next opens the app it checks to see if that date is < 7 days ago, if it is then the app loads if not then it says “Trial over” and exits.

This would be mega easy to “crack” as all you would need to do is either set your system time to way in the future when you first open the app or just edit the record in the table.

You could try to harden this solution by restricting access to the table or some kind of encryption of the date so its not just stored in plan text but in the end if a user if determined to crack your software then he/she will

Kevin Ross
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  • If they uninstall and reinstall it will also fail to detect. I think you're better off storing your values somewhere as a text file on the HD or in the registry. This way they will have to use some kind of File Monitor or Registry Monitor tool to find out where your software is saving it's registration/trial information. – HK1 Oct 20 '11 at 13:32
  • @HK1, that would be easy to find. All the 'hacker' would have to do is look up the data for the linked table and see where it's pointing to. – PowerUser Oct 20 '11 at 15:01
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    Huh? Did I say something about linked tables? I really don't understand your comment. – HK1 Oct 20 '11 at 21:05
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There is a special program named "keyed access" by Petersoft. It makes trial version of Access Applications ...

http://www.peterssoftware.com/ka.htm

khuram
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