We've had this happen too, quite a bit. Seems to be related to a user having a file
open for quite a while, with some sort of period of inactivity, and probably with the files being access from a network location. Here are some other posts on the topic. We haven't really heard of a solution or even nailed it down to a cause. It's hard to duplicate and just seems to happen randomly usually with the above prerequisites.
Save / Save As Post
Copy of Post from Beta Topic: Multiple
open copies causing
save as glitch
joshhuggins wrote:I found this in Paul Thurrott's latest Vista update and thought it could be related to this file in-use bug, which we are still encountering in v.11 in XP Pro SP2 on a domain. FWIW.
Windows SuperFetch
Windows Vista uses a new version of SuperFetch that causes frequently-accessed applications to start up more quickly than is possible on Windows XP. SuperFetch works behind the scenes, examining how you use your PC over time. Then, it prioritizes the caching of applications in RAM based on your usage patterns. SuperFetch also ensures that your applications are given higher priority than background tasks, so the system is always responsive, even if you're stepped away for a while and have just returned.
SuperFetch answers the infamous "lunch" problem which afflicts Windows XP and previous Windows versions. In those systems, a user would walk away from the PC for lunch or some other duration, leaving the operating system to its own devices. Depending on the version of Windows we're talking about, the most-recently used applications would exit the system cache and the OS might begin working on various background tasks. But when the user returned from lunch and started using their applications again, the PC would be sluggish for a while, as if tired from the long time off. In Vista, this doesn't happen anymore. In fact, Vista is smart enough to understand that you may run certain applications at certain times of day. In such cases, it will pre-cache those applications, supplying even better performance.
It's not possible to configure Windows SuperFetch in any way, to my knowledge. It just sits in the background ensuring that your system is always running optimally.