"Getting the data from Africa can be a challenge because the net connection frequently goes down, and he doesn't have reliable electrical power."

So when the IT guy uploads one particularly large data file and it arrives incomplete, no one is especially surprised. Inconvenienced, yes -- e-mail is also down, so the American researcher has to get up at 4:30 a.m. to telephone the African IT guy to report the problem. But not surprised.

The IT guy tries uploading the file again. And again it fails. But this time he notices that halfway through the upload, he's getting a file permissions error.

"Thinking about the problem, I guessed that their server has a regularly scheduled job that periodically goes through and resets the group permissions for the files that are on shared network drives with the Windows PCs," says fish.

"When the job reset the file permissions, the IT guy could no longer write to the file that he created.