If you are setting up a modern development environment, Microsoft recommends installing the .NET Framework 4.8 Developer Pack , as it is the last major version of .NET Framework and includes support for all previous versions (including 4.5) via multi-targeting.
: Used for building applications targeting version 4.5.1.
Download the package (microsoft.netframework.referenceassemblies.net45.1.0.3.nupkg, approximately 18.9 MB)
Includes compilers, build tools, and debugging utilities. System Requirements net framework 45 developer pack link
If your build server or command line throws an error stating that the framework directories cannot be found, your system registry is likely missing the pathing variables.
such as a Windows 7 or Windows Server 2012 virtual machine if you need full .NET Framework 4.5 runtime testing
Windows 10 and 11 ship with .NET Framework 4.8 or 4.8.1 pre-installed as part of the operating system. Because 4.8 is a highly compatible, in-place update over 4.5, the operating system block installs of the older runtime . If you are setting up a modern development
Installation is straightforward, but there are a few edge cases.
Security Warning: Always avoid third-party software hosting websites. Downloading development tools from unofficial mirrors risks exposing your development environment to malware, corrupted binaries, or compromised security certificates. System Requirements and Installation
Download from my.visualstudio.com
However, you can still find official developer packs for its minor updates (4.5.1 and 4.5.2) and use alternative methods to target 4.5 in modern development environments like Visual Studio 2022.
The most forward-compatible approach is to modernize your application. Consider upgrading your project to target or 4.8 , or even migrating to .NET 6/8 (the modern cross-platform .NET). This ensures continued security updates and technical support, as older framework versions no longer receive security fixes.
Follow these steps to successfully install the developer pack on your system. Step 1: Pre-installation Checks Close all open instances of Visual Studio. System Requirements If your build server or command