This is an issue with InstallShield 2012 and later.
You try to compile your script (Ctrl+F7) and you get an error that ‘in previous builds, the msi was only partially built’. Once you start getting this error it persists.
You can try run a full build again (as the message suggests) but it won’t help you.
The solution? delete the entire Release Folder and then rebuild your project. The next time you try to compile, it should successfully get streamed into the msi.