Using a Personal or Family subscription

The minimum that gets installed Outlook working with a Business Basic mailbox.

If you are on Business Basic and do not want to change your business plan, a Microsoft 365 Personal or Family subscription will license the installed apps. The trick is the order you add the accounts in. Get it the wrong way round and Outlook still refuses.

Buy Microsoft 365 Personal (one person) or Microsoft 365 Family (up to six people) from microsoft.com. It is tied to a personal Microsoft account, not your work address.
Install the apps using the Install the Microsoft 365 apps guide on this page, signing in with the personal Microsoft account you just bought the subscription with.
Open Outlook and add that personal account first. This is the step people get wrong. Outlook reads the licence from the accounts signed in to it, so a licensed account has to be there before anything else.
Now add your work Business Basic mailbox as a second account. Outlook accepts it, because the app is already licensed by the personal subscription.
Both mailboxes now sit side by side in Outlook and you can send from either.

Microsoft 365 Personal and Family are licensed for personal use, not business use. They will get Outlook working, which is why we list them as the minimum, but the correct licence for a business is Microsoft 365 Apps for business added to your Basic plan, or an upgrade to Business Standard. Ask us and we will price both for you.

Microsoft documents this behaviour: once any account with a desktop licence is added, you can add accounts whose plans do not include the desktop apps, such as Business Basic. It is not a loophole, it is how the licence check is designed to work.

Family covers up to six people but each person needs their own Microsoft account added to the Family group. Six staff sharing one login is not how it works and will cause sign-in problems.

Stuck on any step? Open a support ticket with support@diskman.net and we will walk you through it.