cannot pread pack file

We have been using git for a year or two now, and suddenly, one of our users got the error message:

fatal: cannot pread pack file: No such file or directory fatal: index-pack failed

while doing a git-pull.  We are using git version git-1.6.5.5.

I tried doing a "git fsck --full" on his repository and on the one he is trying to pull from, and neither shows any error.

If I clone his repository, the clone also gets the error message when trying to pull.

I can pull from him, but if he pulls from me, he gets the error message.

This is worrying, because the fsck doesn't show an error, but clearly something is wrong.

Is there anything further I can try to determine why his repo is unable to pull?

	Thanks,
	Steve

-- 
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