Problem

When you start SmartFTP you get the following error message:
The program can't start because api-ms-win-crt-runtime-l1-1-0.dll is missing from your computer.

Cause

The problem is that the KB2999226 (Universal CRT), which is part of the Visual C++ Redistributable, failed to install. The Universal CRT fails to install if the necessary prerequisites (other updates) have not been installed yet.

Solution

1. Install Windows Updates:
   Go to Start - Control Panel - Windows Update
   Check for updates
   Install all available updates.
   After the updates are installed, restart your computer.
   After the restart repeat the steps above again until no more updates are available.
    
2. Download the Visual C++ Redistributable:
   
   For Windows x64 (64-bit)
   Visual C++ Redistributable for Visual Studio (64-bit)
   For Windows x86 (32-bit)
   Visual C++ Redistributable for Visual Studio (32-bit) 
   
   
3. Run the vc_redist.x64.exe (64-bit) or vc_redist.x86.exe (32-bit) and select Uninstall
4. Run the .exe again and select Install 

Alternative Solution

If the solution above fails, upgrading to Windows 10 will mitigate the problem because starting with Windows 10, the Universal CRT is part of the operating system.

References

1. Microsoft Download - Visual C++ Redistributable for Visual Studio 2017
2. Visual C++ Redistributable fails to install
3. KB2999226: Update for Universal C Runtime in Windows