Trend Micro Inc. is warning that some companies may experience computer trouble Monday due to a bug in antivirus software that disables local area networks.

The software publisher said Sunday it did not detect the bug in an update released Saturday morning because it did not conduct pretests on relevant operating systems and incorrectly conducted tests on other systems.

It said the bug-infected file has been replaced with a bug-free one.

Still, firms and governmental bodies that were closed Saturday and Sunday may experience trouble Monday if their servers automatically updated the software between 7:33 a.m. and 9:20 a.m. Saturday.

According to Trend Micro, problems were found at 61 media organizations and other companies in Japan, the United States and Australia.