A flaw in the way Windows Home Server works with certain Microsoft applications, such as Windows Vista Photo Gallery, could result in corrupted files.
According to Ed Bott over at ZDNet, the response from Microsoft is as follows:
This is not an issue that affects every Windows Home Server installation, and the symptoms require several factors that are not mentioned in the KB article. The largest contributing factor is when a home server is under extreme load. If you’re doing a large, highly demanding file copy operation in the background and you’re using one of the listed applications to edit a file that’s stored on a shared folder on the home server, and you save the edited file to the server, then you might see this bug.
The main culprit seems to be if you’re putting Windows Home Server under a heavy load, and I doubt many of the people running the software have reached that point yet.
You can find a list of the specific applications in the support document.