Can't upload existing keystore?

Hi guys, I am trying to make an update form my app which is already on Play Store.
However, when I try to build the apk,I first go to Player Settings-> Publishing Settings, I check “Use existing keystore”, I click “Browse Keystore”, but I can’t select it from the folders view window. I see it, when I go to its location, but it is not selectable, it has a gray-ish tint. Note that I am working on a MAC, maybe this has something to do with it.

Can anyone please help me?

oops, nevermind. Turns out the file didn’t have the .keystore extension. I added it at the end of the file name and it now works.