Currently, Razer does not offer an official standalone offline installer

Manual Transfer (Advanced)

: Some users attempt to copy the installed folders from C:\Windows\Installer\Razer\Installer\ from an online PC to an offline one, though this is not officially supported and may lead to stability issues. System Requirements

If you live in a rural area or have a metered connection, downloading 200+ MB every time you want to install or reinstall Razer Cortex can be frustrating. Worse, if your connection drops mid-download, the installer may fail and force you to start over.

The Ultimate Guide to the Razer Cortex Offline Installer: Why You Need It and How to Get It

Cause:

You actually have the online stub installer. Fix: Redo Method 1 and ensure you copied the large temp file (not the original 2MB launcher).