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Managing the demo version of software RRS feed

  • Question

  • I have a software product written in VB6. It is a paid software product and it has a demo version for trial period of 1 month.There is no separate setup file for demo version.The software on entering the product key turns demo to a full version.I used to write the information in registry to track the 1 month for demo version and after that software will not work. Also if windows user is not admin then registry cannot be written to HKLM. If i write registry to HKCU the user can create new user and reuse the software by installing it. So how can i manage the demo version to 1 month and user cannot use it after 1 month without purchasing the key?
    Monday, February 18, 2013 11:52 AM

All replies

  • People ususally solve this type of problem by requiring an internet connection and your company providing a web service that the program calls at startup, having generated some unique id that identifies the machine or user (or the web service provides one at first call). Then your company keeps track of when it was first used.

    Phil Wilson

    Monday, February 25, 2013 6:54 PM
  • Hi PhilWilson..

    But the problem is that user may not connect to internet. Also our software does not need internet for it's working.There are so many customers who use software without having internet connection.so i can't go with this method. So what method i can use other than this?


    Tuesday, February 26, 2013 12:35 PM
  • I don't think there is. A user could start up a fresh virtual machine every day and run your app forever. If you don't have an internet connection then all you can do is record something in the registry when the user first uses the software then tell them when the trial period has expired. You need to accept that a determined user can hack at thir machine to undo anything you have in the registry or in a file. Maybe they would uninstall it and re-install it and start again, depending on how your code works. Unless you can record the user activity at a machine you own, there's no foolproof mechanism.

    Phil Wilson

    Tuesday, February 26, 2013 5:43 PM
  • I want to store a registry in HKLM for checking whether demo is expired or not. But problem is if the user does not have admin permission then i cannot write registry to HKLM. So how to write registry to HKLM?

    Monday, March 11, 2013 4:50 AM
  • That's an issue, so why not use HKCU? The larger question would be if that is the only thing the app does that requires admin privilege. If you're not admin, there are plenty of file locations you can't use in your app, and you can't install to them either.

    Phil Wilson

    Monday, March 11, 2013 5:06 PM
  • Hi PhilWilson

    If i write in HKCU then it applies to only that user. So each user has separate registry for this .So i can't use it because user may create another user and install the software and use it. So what is the solution for this problem?

    Wednesday, March 13, 2013 6:02 AM