A Microsoft outage that began about 3:15 am AEDT on a Friday and knocked out Outlook and other Microsoft services for more than 12 hours is expected to cost Australian businesses billions of dollars, with experts saying small businesses will be hit hardest and the financial impact lasting weeks. Among those affected, Queensland's Regal Shower Screens put the lost day at at least $30,000, while industry figures say the episode shows businesses need backup and contingency plans.