OK, well, I think you should read this
. 'Unstable' builds are for testing only - it's not intended that people import their serious, important projects to unstable builds to continue them - precisely
because of what happened to you! Things can be seriously broken in unstable builds (in fact, you should expect it), so the plan is everyone imports their .caps, gives it a quick run to check if everything's working, and if it's not, file a bug report. Then keep using the last stable build and only upgrade to the next stable build!