compiler error when entering play mode

when entering play mode, get error message: “all compiler errors have to be fixed before entering play mode.” Console says:

Assets/Standard Assets/Image Effects (Pro Only)/ColorCorrectionEffect.cs(6,14): error CS0101: The namespace global::' already contains a definition for ColorCorrectionEffect’

I added some tutorial assets, then got this state to my project . Creating a new project does not help…
How to fix this?

“already contains a definition forColorCorrectionEffect” is telling you that you have added ColorCorrectionEffect twice to your project.
Look to see if you have two copies, and delete one. I’d guess you were following along, grabbed that file and thought it didn’t work, but you really put it in the wrong folder, then tried again and got copy #2 in the correct folder.

You’d think since they are the exact same, having two copies would be fine – it won’t matter which one it runs. But it’s a pain to check they are identical, and one could be changed to be different later. So easier to yell at you now to pick just one.

ok thanks! Is it ok to delete a script, or module? Is there any advice how to organise folder structure to avoid this?