Microsoft has made it virtually impossible to open certain types of file attachments in the latest version of Outlook included with the new Office XP business software suite.

Outlook 2002 users will find that more than 30 types of files will be automatically rejected. These are files that have been deemed by Microsoft as the ones most likely to be used by hackers to transfer email viruses such as the I Love You bug.

However, this measure could cause as many problems as it solves, because included in the hit list are many common program files, Windows help files, images and screensavers. This will make it more difficult to share routine, harmless information via email.

While Outlook 2002 doesn't actually block restricted emails, it will refuse to open or download restricted file types. It will also be very difficult to disable the feature and, although the software is due out at the end of this month, Microsoft is holding back before publishing instructions on how users can do this.

The software company has tried bans before when it has released security updates for Outlook. However, applying the restrictions has always been left to the discretion of individuals or companies.

Microsoft is saying that it needed to take the Draconian measures because so few people were applying the security updates and that the restrictions will also encourage good email practice.

Users will be forced to compress files intended for other Outlook 2002 users rather than sending virus-friendly executable attachments. Critics, however, point out that the restrictions do nothing to rectify any inherent security problems in Microsoft products and could lull people into a false sense of security.