"Oops" error while installing SQL Server 2017 developer edition on Windows 10
Neither the localized version nor the ENU help .chm file exist in the media. This could mean that there is no appropriate help file to display on the UI. Error message: The help .chm file 'C:\SQLServer2017Media\RulesEng\1033_ENU_LP\x64\1033\help\s11ch_setup.chm' is missing from the media
As per my understanding,this issue arises when setup files are not downloaded completely..
You may have to download entire setup first and install it later as shown in screenshot below
If anyone is still having issues with this. Instead of choosing the basic installation, I choose the custom options. It took a few more minute than it would have taken with the basic. Maybe this will work.