Microsoft posted a couple of days ago on the WHS Team Blog about a hotfix for fixing a PC Backup issue.

Essentially, backups may fail if the drive uses NTFS Compression. This is not to be confused with compressed files (like ZIPs or RARs), but compression at the file system level. Most people don’t use this, it’s primarily for archived drives that want to maximize storage of every last sector.

From the hotfix’s web page:

“Under certain circumstances, a compressed file may consume more disk space than the original file size. Some sections of a file may use less disk space after NTFS compression. However, other sections of a file may use more disk space after NTFS compression. 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.”

The update will be made available on Windows Update in the near future (the next Patch Tuesday). However, click the link above to grab the update now. Unfortunately, because this is a bug in the connector software, it must be installed on every client PC, not the server itself.

And no, this is not the major file corruption bug that still plagues WHS. And, will still plague WHS after Power Pack 1 is out…