Xcode 10 Error: Multiple commands produce

This answer is deprecated - Xcode 12 has deprecated the Legacy Build System, it will be removed in a further release

I found the solution for this build error, for anybody else having the same issue with Xcode 10 build system, follow the following steps to fix it:

1. In Xcode, go to File->Project/Workspace settings.
2. Change the build system to Legacy Build system.

It will resolve the build issue with the new Xcode 10.

If you want to work with the new build system, then you can find the troubleshooting help from this apple Xcode help page.

The issue might be occurring because of multiple Plist or other files within App-

Solution -> Open target -> Build phases > Copy Bundle Resources and remove info.plist from there.

Note: If you have developed a watch app too then you will have to remove the plist from the watch and watch-extension too.