PRIMARYFOLDER

Do not change its value directly; instead, go to the Files and Folders project page, right-click on the desired primary folder, and choose the Set as Primary Folder command from the folder's context menu.

Because this is a public property, you can also set it on the installer's command line.

You can refer to this variable as <PRIMARYFOLDER> (Tarma native syntax, preferred) or [PRIMARYFOLDER] (Windows Installer syntax). Because the variable contains the alias of the actual primary folder, you can retrieve the primary folder path (as opposed to the primary folder alias) by using double indirection: <<PRIMARYFOLDER>>.

Windows Installer does not support double indirection of variables, but some dialog controls have an Indirect attribute that effectively provides double indirection.