Microsoft released the Security and Quality Rollup update (KB4345590) for .NET Framework for Windows 7 and Windows Server 2008 systems earlier in August 2018.
The update installs fine for most users, but some of us are having trouble installing the KB4345590 update. The update fails to install even after a restart of the PC.
Thankfully, the issue can be fixed by installing the KB4345590 update manually. Download the update file appropriate for your system from the link below and follow the instructions to install it.
To install the update, Double-click/run the .msu update file. You’ll get a prompt from Windows Update Standalone Installer, click on the Yes button to install the update.
Once the installation completes, restart your PC for the update to take effect.