While trying to install SQL Server 2017 RC 2 Developer Edition on a Windows 10 clean image (VMware Workstation 12) that has Visual C++ 2015 redist (version 14.0.24215) already installed, the installation of the Database Engine Services and Full-Text and Semantic Extractions for Search components (and likely others) fails with the message:
Error installing Microsoft Visual C++ 2015 Redistributable
VS Shell installation has failed with exit code 1638.
Error code: 1638
Log file: C:\Program Files\Microsoft SQL Server\140\Setup Bootstrap\Log\20170808_231223\VCRuntime140_x64_Cpu64_1.log
Visithttps://go.microsoft.com/fwlink?LinkId=20476&ProdName=Microsoft+SQL+Server&EvtSrc=setup.rll&EvtID=50000&ProdVer=14.0.900.75&EvtType=VCRuntime140_x64%40Install%400x1638 to get help on troubleshooting.
The version of the VC++ 2015 redist files in the ISO appear to be 14.0.23506.0 which is older than what's already installed.
(Also note the lack of a space after the word "Visit.")
(This also happened with RC 1.)