What a two-day Microsoft 365 outage actually means for a contractor, a dental office and a bookkeeper

The Microsoft 365 outage that began Thursday ran into a second day on Friday. Microsoft said it has "no evidence of malicious activity associated with this incident," and that it extended its email timeout window to 48 hours so delayed messages are held rather than bounced, Fox Business reported. The BBC reported the same extension and said customers had varying access: some could not send or receive email, view files or use calendars, while others could use Teams normally. The New York Times said Microsoft described service as improving by 9 a.m. Eastern Friday. We cover the outage itself in our update. This is the owner\'s version.

Put a number on it

Suppose each person on staff loses four working hours a day to email and calendar trouble, and an hour of staff time costs $30 with payroll costs included. Two days of that is 8 hours per person, or $240 each.

• A five-person contractor: 5 x $240 = $1,200.
• A 12-person dental office: 12 x $240 = $2,880.
• A 25-person distributor: 25 x $240 = $6,000.

These are assumptions, not measurements. The cost is smaller for people who live on their phones and in the field, and larger for anyone whose day is scheduling. The bigger risk is not wasted hours but a missed deadline: a change order, a bid, or a patient confirmation.

Three businesses, three different problems

A contractor. The danger is paper that moves money: quotes, signed change orders, lien waivers, supplier confirmations. A customer who never saw your approved quote may not know they approved anything. Call or text anything with a dollar amount or a start date, and write down who you told. Material orders sent Thursday may not have reached the supplier, so confirm delivery for Monday jobs.

A dental office. Appointment reminders and patient emails can sit in a queue. Reminders sent late mean empty chairs the next morning. Call tomorrow\'s and Monday\'s patients if reminders normally go out by email, and avoid sending patient information through a personal email account as a workaround; that creates a privacy problem on top of an outage. Protect Monday\'s schedule first.

126,946 independent dental practices are listed on CheckThisBiz, a directory of 7,704,724 independent US businesses, including 19,080 in CA, 11,032 in TX, 8,104 in FL. Chains and franchises are excluded from that count, so these are the owner-operated businesses that actually apply for funding.

A bookkeeper or small accounting firm. Clients send documents by email near month-end. If someone sent you a statement or a payroll change Thursday, assume it is not in your inbox yet and that a 48-hour window counted from Thursday afternoon (our arithmetic, not a Microsoft deadline) runs out around Saturday afternoon. Check before you close the books or run payroll on numbers you think are final.

The thing most owners will get wrong

The instinct is to resend everything. Microsoft\'s longer timeout means original messages may still arrive, so a flood of duplicates leaves customers wondering which version is current. Resend only what is urgent, and label it ("Resending: original sent Thursday, please confirm receipt"). The opposite instinct, changing every password because "it might be a hack," is also unnecessary on current reporting: Microsoft says it has no evidence of an attack, and the outlets above have found none. Do change passwords if you have your own reason to.

What to do this weekend

• Make a list of every email you sent Thursday and Friday that carried a deadline or a dollar amount, and confirm each by phone or text.
• Before the 48-hour window closes, check whether messages you expected have arrived. After it, anything missing is worth asking for again.
• Write down when your mail stopped working. If your contracts or Microsoft\'s terms address downtime, you will want the hours.
• Pick a backup way to reach your five biggest customers that does not depend on one email provider. Doing this on a quiet Saturday beats doing it during the next outage.

If your email is already working normally and nothing you sent was urgent, the right move is to do nothing beyond checking.

Sources: Fox Business; BBC News; The New York Times; business counts from CheckThisBiz. Staff numbers, hours and wages are illustrative assumptions. This is general information, not legal or investment advice.