Every so often when I run git add . to add new files to my repo my git index will reset and think all the files in the repo have been deleted. I run these commands:

git status
git add .
git status
git commit -a -m "Commit message"

everything looks fine at all those points until I commit and it says every file was deleted, all I have to do it run git add . and commit again to get the files back, but this becomes a pain. And this doesnt happen every time, maybe about 40% of the time. Anyone know why this might happen?

I am on Mac OS 10.6.3 with Git 1.6.6