FCP Project clips say 'missing event'

FCPx is giving me the spinning ball when I try any edit command, i troubleshooted this problem using a troubleshooting guide and I created 2 hidden folders, one for projects and one for events and dragged what I wasn't working on into these hidden folders, but now the project I'm working on says 'missing event' when I skim thru them the clip briefly flashes up but then goes back to the red message saying 'missing event'
Any thoughts on this would be greatly appreciated.
S

What version of FCPX?

It sounds like one of the events you moved to a hidden folder was being used by the project.