Two tenants, one practice. Your security is set by the weaker one.

Two offices, two Microsoft 365 tenants, and nobody can see anyone's calendar. I see this every time a practice grows.

When you open a second location or bring another practice under your roof, you usually inherit their Microsoft setup instead of absorbing it. Now you're running two of everything: two directories, two sets of security settings, two bills.

Microsoft does have an answer. You can link tenants into what they call a multitenant organization, so your people can find each other, see calendars, and work together in Teams across both sides. It supports up to 100 tenants, far more than any practice needs.

But linking is not merging. Microsoft's own documentation puts tenant consolidation out of scope, and a newly shared user can take up to seven days to show up in search. Don't plan your go-live for the Monday after closing.

Here's the real risk. Your security is now set by the weaker of the two. If the office you just brought on never turned on MFA and never closed out old accounts, that's the way in, and the bridge you just built is how someone walks to the rest of your practice.

So go through the other tenant the way you'd go through their books. Who has admin. Who has MFA. Which accounts should have been shut off years ago.

If a second location is on your 2027 roadmap, that review is worth doing before the paperwork is signed.