The current Windows installer for vapor 2.6 is missing MSVCP140.dll, for Windows 10 Pro.
To reproduce:
Install vapor on Windows 10 Pro and try to run it.
Quick fix:
Install the follwowing:
https://www.microsoft.com/en-us/download/details.aspx?id=48145
Long term fix:
In visual studio, go to Project tab -> properties - > configuration properties -> C/C++ -> Code Generation on runtime library choose /MTd for debug mode and /MT for release mode.
Details here:
https://stackoverflow.com/questions/32998902/msvcp140-dll-missing