Windows Home Server users, already worrying about the possibility of data corruption when directly working with files stored on a multiple-drive-equipped WHS system, have a second problem to worry about: what happens when WHS backs up files stored using NTFS compression? As KB 950190 reveals, the results might not be pretty:
If the compressed file uses more disk space than the original file, a small amount of data at the end of the file may be lost during the backup process. This data loss results in a corrupted file or a partially-corrupted file, depending on the corresponding file types. The file types that may be affected by this issue include, but are not limited to, CAB, ZIP, JPG, and PNG.
Fortunately, KB 950190 also provides updates for the Windows Home Server Connector software (and the updates will also be coming through on Windows Update).
When will there be an update for the direct-access data corruption bug in WHS? The latest estimate is June. In the meantime, read KB 946676 and follow its recommendations.