Large Inno Setup installer with compressed data outside the installer binary

I've made a large installer (around 5GB) and it works fine, however since the main installer is very big it tends to take a while between double clicking it and actually getting the installer window.

I've noticed some other big installers simply seem to bundle the compressed files to be installed in some external file and the installer itself is only a few MB.

How can I accomplish this with Inno Setup? There's the external flag however it doesn't compress the files etc:

external This flag instructs Inno Setup not to statically compile the file specified by the Source parameter into the installation files, but instead copy from an existing file on the distribution media or the user's system. See the Source parameter description for more information.

Thank you.


  • Try using "disk spanning" feature:

    DiskSliceSize=1073741824 ; 1 GB