SDK is not defined for Run Configuration

When I'm trying to run my project in PyCharm I'm getting an error:

SDK is not defined for Run Configuration.

I tried to set a new interpreter and tried everything.

What does "SDK" mean and where can I configure it?

error popup on run button

Solution

I just had this same issue (see my comment above). What worked for me was to go into "Edit Configurations", delete the configuration that was copied over from the original PC, and create my own configuration (basically with the same inputs as before).