Because Microsoft has largely abandoned this download link, many third-party sites offer "dotnet 1.1 sp1 64 bit free download". 90% of these contain malware, adware, or injectors.
Safe download sources:
Always verify the digital signature: Right-click the .exe > Properties > Digital Signatures tab. It should show "Microsoft Corporation" with a timestamp from 2004-2006. microsoft net framework 1.1 service pack 1 64-bit download
Microsoft .NET Framework 1.1 Service Pack 1 (SP1) 64-bit Download
The following feature can be considered for Microsoft .NET Framework 1.1 Service Pack 1 (SP1) 64-bit: Because Microsoft has largely abandoned this download link,
If you have legacy enterprise software (like an old ERP system or a specialized government app) that refuses to die and requires .NET 1.1, you have three difficult options:
Option A: Windows 7 Virtual Machine (The most stable) Since Windows 10/11 won't touch it, spin up a Virtual Machine running Windows 7 (or Windows XP if you have a license). Install .NET 1.1 SP1 there. Always verify the digital signature: Right-click the
Option B: The "Franken-build" (Not recommended) Some tech forums provide a slipstreamed version of the installer where users have hacked the MSI (Microsoft Installer) files to bypass the version checks on Windows 10. This is risky, unstable, and generally not something you want on a network-connected production machine.
Option C: Rewrite the App This is what Microsoft wants you to do. Move the application to .NET 4.8 or .NET Core/6+.