Check for Previous Install
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This action checks the target system for a previous install of your application and sets up virtual text variables as a result.  When searching for a previous install, InstallJammer uses the Application ID of your project to find them.

The following virtual text variables are set as a result of this action:


Version 1.0 of InstallJammer only defined the <%PreviousInstallExists%> and <%PreviousInstallDir%> variables.  You should use a Virtual Text Exists Condition if you are unsure of whether the previous install virtual text you want exists.

If <%PreviousInstallExists%> is false, none of the rest of this virtual text is set.


The Application ID of the previously installed application.  This should match your own Application ID unless the previous install was an upgrade install.  In that case, the Upgrade Install ID should match your application ID.


The install date of the last install in clock seconds.  This can be formatted using the <%Date%> virtual text.


The number of previous installations found on the target system.  Only the last install, by date, will be used for this information.


The installation directory of the last install.


A convenience value that tells you whether or not the previous install dir still exists on the target system.


The full path of the previous install executable when it was run.


This value will be true if a previous install was found, or false if one was not found.


The Install ID of the last install.  This is the ID that is generated everytime an installer is run, so this ID will change with each subsequent install.


This virtual text contains a list of all previous install IDs that have been installed for this application.


The real username of the person who installed last.  This is the real username even if the user was running as root.


The directory where the previous installer was run from.


The full path to the uninstaller of the last install.


The Upgrade Application ID of the last install.


The username of the person who installed last.


The install version (, etc...) of the last install.


The install version string (1.0a1, etc...) of the last install.


Other variables can also be set if a developer has added information to the install registry through the Add Install Info action.  Any variable added through that action will also appear in virtual text as a result of this action.  For example:

If the Key Foo was added with the Value Bar, you would get the variable <%PreviousInstallFoo%> that would equal Bar.

Standard Properties 

See Standard Action Properties.