Project says missing 4 proxies?

What could be the reason for this, any help would be appreciated.
S

Guess: You are using proxies and haven't generated them for ALL the media used by your project. I think I get that when including stills and forgetting to have the "create proxy media" box checked in the import preferences.

Thanks, how do I generate them as I have the proxies box ticked now?

What version of FCPX? Your use of "box" makes me think of the box in preferences which went away in 10.1.

This answer is for 10.1. To generate proxy media control/right click on a clip and pick "Transcode Media...". That will open a sheet where you can check "Create proxy media" and then click OK. Or, you can open the inspector for a clip and select the "Info" tab. It will tell you what media is available. If the proxy indicator is red (no proxy media) a button is will also show up that when clicked will generate proxy media. WARNING! Sometimes this tells me I have proxy media available when I know I do not. That may be because I'm playing in test projects where I've gone in and deleted media that was once generated. Don't know.