Hi Namik and welcome to Advanced Installer forums.
Thank you for your interest in Advanced Installer.
In order achieve what you want you can create another VBScript that will remove the related local user.
If the "Edit Prerequisite->Options->Force installation of this prerequisites" checkbox is checked you can add the remove user VBScript custom action in the "InstallExecutionSequence->Rollback" action group.
Also, if the "Edit Prerequisite->Options->Force installation of this prerequisites" checkbox is unchecked, then you can proceed like this:
- select the "Edit Prerequisite->Options->Global prerequisite installs before main MSI package" radio button option for your prerequisite package
- then go to the Search page and create the searches that you are using in the "Edit Prerequisite->Install Condition" tab for your prerequisite
- add the remove user VBScript custom action in the "InstallExecutionSequence->Install" action group
- in the "Execution Condition" of the above custom action use the above searches you created in the Search page
Let us know if it helped, otherwise give us more details about your scenario.