If you need the for OpenIV 4.1 (rather than the web launcher), follow the points below.
https://openiv.com/OpenIV_Setup.exe SHA-256: 9a3f1d8e... (verify on openiv.com) openiv 4.1 offline installer download
OpenIV is the essential modding tool for Grand Theft Auto IV, Grand Theft Auto V, and Max Payne 3. Version 4.1 is a significant release, introducing support for newer game updates and improving archive management. If you need the for OpenIV 4
If you absolutely need an offline installer for repeated use on multiple PCs without internet, download the official online installer once, run it on an internet-connected machine, and then copy the installed OpenIV folder from %ProgramFiles%\OpenIV to a USB drive. This portable copy works offline. Grand Theft Auto V