How does trial software version work & know when to stop?

Trialware or Trial Software, is computer software that can be run for a limited period of time before it expires and stops working. The idea behind this concept is that the user gets a chance to try it out and then decide whether he or she would like to buy its full version. It is actually a sample of original software that works for a limited period of time. It may or may not have all the features of original software. In either case, it ceases to work after its time-limit expires. This article talks about how a trial version software works.

How does trial version software work

There are many methods that are used by programmers to know when the trial period of a software has elapsed. In earlier times, something as basic as checking the system date was  done. But over a period of time sophistication has entered.  Since no two programmers think alike all the time, there can be no certain method to be explained in this context.

Creating hidden registry entries

Some trialware makes entry into the Windows registry about when it was installed, along with the time of installation. The software, when launched, compares the registry noted date and time with computer date and time. If the latter is greater, the trial version of the software or trialware, as it is called, stops functioning. But this is the easiest method that can be employed by any trialware. Such entries are not created in obvious places under obvious names, but instead are ‘hidden’

Since programmers too know that it is easy to scan registry with program remnants and reinstallation for use, they might add few more hidden registry entries that do not look related to the trialware. That means, when you install a trial version of a software, it may create a few registry entries in say, HK_LOCAL_MACHINE or HK_CLASSES_ROOT where normally, no user will look into. Further, the names of keys would be unrelated to the program so that even if a user is figuring out keys to delete, he or she does not know if a key belongs to the trial version of a software. That way, programmers can prevent a working reinstallation of the trialware.

Trial software use hidden and system files

Some programmers create hidden files or system files related to the trial version of a software and place it in System32 folder or into the folder containing drivers. They could even be 0 byte or empty files. If they add an extension that goes .sys or .ini, users will think twice before even editing the files. Junk cleaners too will ignore them.

Further, the files can be encrypted and if users try to make any changes, the trial version completely stops working as result of manipulation of the related files. In this case, when the program is installed, it creates several files in different locations, especially the ones that are related to Windows functioning. Based on the data written to these files, the program can detect if the trial period is still remaining or if it has expired. This is another explanation of how trial versions of software work.

Trialware use Computer MAC address

In this case, the computers’ address is stored to the servers of the software publishing company along with other details such as data and time and probably a snapshot of the volume containing hidden files. These hidden files have been explained in the above section. This storage of MAC addresses of the computers or smartphones helps the trialware in deciding two things. First, if the trial period has been expired. And secondly, it tells the computing company that if the user is trying to install another version of the trialware on the same machine.

For example, user can download the Student Edition of Microsoft Office to a machine. The address of the machine is stored to Microsoft’s server. After the trial period of 90 days, if the user attempts to download and install another Student Edition of Microsoft Office to the same machine, Microsoft knows it and prevents installations.

This method prevents a working reinstallation of the trial version of a software, even if the user formats his Hard Disk Drive. The MAC address of the computer or smartphone or tablet registered with the publishers’ servers will tell the program that it was installed once on the program. The drawback could be that if the user tries to reinstall the program after a format even before the trialware’s trial period expired, she or he may not be able to reinstall a working copy.