This tells the Setup Compiler which type of Setup to create. If this is yes, it compiles all setup data into a single EXE. If this is no, it compiles the setup data into at least three files: setup.exe, setup-0.bin, and setup-1.bin. The only reason you would probably want to use no is for debugging purposes.

Note: Do not use UseSetupLdr=no on an installation which uses disk spanning (DiskSpanning=yes). When UseSetupLdr is yes, the setup program is copied to and run from the user's TEMP directory. This does not happen when UseSetupLdr is no, and could result in errors if Windows tries to locate the setup.exe file on the disk and can't find it because a different disk is in the drive.

Note: Do not use UseSetupLdr=no to avoid digital signature verification startup delays on a large Setup, use disk spanning instead. See SignTool for more information. Also note that digitally signing a UseSetupLdr=no based Setup will lead to an invalid digital signature for Uninstall.