Why is the Run option disabled on PyCharm?

If you're creating a project from existing source: and If the existing source directory contains a lot of data/files:

• the Run option (and others, assumably) are disabled until PyCharm is finished indexing the contents in the project. You'll see a progress bar in the lower-right-hand corner.

You can speed this up by right-clicking on folders and selecting "Mark directory as..." -> "Excluded" if they aren't to be indexed.

Right click inside your main file & then you get Run option!

You can't run without a configuration, however temporary configuration can be created automatically if you use Run context menu option in the script editor.