Even with the correct MSI, issues arise. Here is the fix list.
If you have access to a machine with internet access that can download packages for transfer, the most reliable way to get an "installable" package is via Chocolatey (the Windows package manager).
Chocolatey often hosts the full package (.nupkg or the extracted binaries) rather than just the bootstrapper. telerik justdecompile offline installer link
Steps:
The offline installer requires .NET Framework 4.7.2 or later. Download the offline .NET Framework installer from Microsoft first. Even with the correct MSI, issues arise
Telerik JustDecompile remains a top-tier tool for developers who value a clean interface and Visual Studio integration.
However, if your specific requirement is a strictly offline installation (for example, on a secure development server with no internet access), JustDecompile is no longer the best choice. In that specific scenario, dnSpy is the superior alternative because it is fully portable (a single executable file that requires no installation or internet connection). Telerik JustDecompile remains a top-tier tool for developers
Recommendation: If you have internet access, download the official installer from the Telerik website. If you need a true offline tool, switch to dnSpy.