When saving your project in Delphi, it often compiles both the executables (exe) and DCU files on the same folder location. Although it is the standard procedure, this process can be a little confusing if you are using different versions of Delphi. It turns out, all files from different versions of Delphi will be outputted on the same folder which might not just lead to confusion but also strange compile errors.
To avoid these strange compile errors related to DCUs, Alister Christie from Learn Delphi TV will demonstrate how you can output your DCUs and executables into different folders for each version of Delphi. This Learn Delphi video will also discuss the environment variables and how you can add a new product name and save the files on that specific folder. To learn more, feel free to watch the video tutorial above.