Troubleshooting

Make sure that you have correct version of Photoshop
Most scripts require at least Adobe Photoshop CS6. Some of them can be run in earlier versions but its work is not guaranteed. Refer to corresponding post to check version requirements.

Make sure you have installed script in the right directory
To get access to Script from File → Scripts menu you have to move script files to the correct directory.
Usually it is directory where Photoshop.app is located. For example, on Mac it will be:

/Applications/Adobe Photoshop [VERSION]/Presets/Scripts

For Windows machines, double check what version of OS are you using. 32 and 64 bit versions of OS have different directories where you can find Photoshop. Again, best way to locate correct directory is to check where’s Photoshop executable file is located.

Read carefully installation instructions
Some scripts can have additional steps for installation. Please read carefully instructions in corresponding post.