After installing XE 2015, but still using XE 2013 to build a project, I got this warning, and corresponding error that the DLL was not found:
HEADTANK: warning: TargetPath(C:\Open\kwc54dw\Dev\Winyldmd\trunk\HEADTANK\Release\HEADTANK.dll) does not match the Linker's OutputFile property value (C:\Open\kwc54dw\Dev\Winyldmd\trunk\HEADTANK\Release\yieldmod.dll). This may cause your project to build incorrectly. To correct this, please make sure that $(OutDir), $(TargetName) and $(TargetExt) property values match the value specified in %(Link.OutputFile).
For this project, as indicated, I am not using the default Target Name, but in the configuration properties for the compiler, this has been changed back to $(ProjectName) instead of the previously specified name (yieldmod).