Sometimes when you open a project you can see it has a reference warning. In the Projects tab the project name is red, and the icon shows a warning symbol, as seen below:
The window displays the missing file, the problem, and a possible solution. In this case the project probably used a literal path to the file keystore.ks. Clicking the Resolve... button opens a file browser so you can find the missing keystore file. The default location is as follows:
Locate and select the file. You receive confirmation that the problem is resolved, and you can now click Close.