Previously I reported on how Microsoft Live OneCare was one of only four security applications that failed to receive certification in a field of 15 security apps. Now there's worse news: If OneCare finds a virus in your inbox, it might delete your entire email file. All of it. Wow.

Since Outlook stores email in a single, gigantic file (typically a .pst file), you can see how it happened: OneCare deemed the file to be contaminated, so it simply deleted the file. Not a good solution, no. I can assure you that I will never, ever, ever, ever install OneCare on any computer I own except for (brief) testing and on an isolated machine.

What makes this issue particularly loathsome is that the problem is actually a year old. Microsoft fixed it, then abruptly it happened again when a recent update was released.

Evidence continues to pile up over OneCare's incapabilities. Another independent test of 17 anti-virus applications [PDF link] found OneCare to be the only one that didn't pass the test, achieving no certification at all. OneCare scored an 82.4 percent detection rate, by far the lowest of the group, with specific weaknesses in a variety of areas. (It's worth noting that McAfee also barely scraped by in this test; it had failed the earlier certification mentioned above along with Microsoft.)

OneCare is bad, but is that symptomatic of Microsoft's impending doom? Check out this recent commentary called "Microsoft's meltdown," which justifiably asks if a lack of trust in Microsoft's products could be the beginning of the end for the company. I don't know if things are that dire, but I certainly haven't seen much good coming from the company lately.

Oh, and Microsoft's response to all of this? It put out a patch. Meanwhile, users are still complaining they can't recover their deleted email files...