Microsoft Corp. has released a patch to its popular Outlook eMail program to protect against viruses like the “ILOVEYOU” bug that caused billions of dollars in damage in May.

The patch, in its default mode, prevents Outlook users from running any “executable” program attachments to eMail, good or bad. As an additional safeguard, any time a computer program attempts to access Outlook’s address book or tries to send eMail via Outlook, users will receive a warning and be urged not to allow it.

Microsoft added options for corporate users, allowing them to choose which attachments users on their networks could access. Adding the extra capabilities delayed introduction of the patch for more than two weeks.

The software patch for Microsoft Outlook 98 and Office 2000 was available on a company web site starting June 8.

The “ILOVEYOU” virus clogged eMail systems around the world and infected millions of computers, destroying graphics files stored on many machines. It worked only against users of Microsoft Outlook and caused as much as $10 billion in damage, mostly in lost work time.

The patch is available as a free download from http://www.officeupdate.com.