Check what each Microsoft account can access
Write down each account and calendar you intend to use. An Outlook.com personal account and an organization-managed Microsoft 365 account may have different consent and sharing policies. Approval in one organization doesn't grant access to another.
Sync My Cal works with connected Microsoft calendars that the account can access. The destination must allow writes. Don't assume a shared mailbox or delegated calendar will be available: confirm that it appears in the picker with the access your rule needs. If an administrator blocks access, get approval before continuing.
If you only need to read several calendars together, your Outlook calendar view may be enough. For an internet calendar feed, Microsoft's import and subscription guide distinguishes a one-time import from a subscription that refreshes. Neither is the same setup as managed copies between your connected accounts.
Decide who needs to see busy time
For a personal appointment to reserve time at work, personal Outlook is the source and work Outlook is the destination. Use Busy blocks so the destination receives availability without the appointment title, description, or location.
Add a separate work → personal direction if you want work meetings on your personal calendar. A two-way setup sends originals in both directions; it doesn't turn copies into shared, jointly editable originals.
With three accounts, use direct rules for every destination that needs an original's availability. Managed copies don't become sources, so a personal calendar in the middle won't relay one client's copied meetings to another.
Connect and test one calendar pair
- In Calendars, connect the first Microsoft account. Check the account shown on the consent screen.
- Connect the next account and select the calendars you want to use. Check their names and account labels; two different accounts can both call their primary calendar “Calendar.”
- Open Syncs and choose the source and writable destination. Select the privacy level for this direction.
- Review filters. Busy-block presets skip all-day and declined events; change those settings if an all-day commitment should block your work calendar.
- Preview and save the rule. Create a timed test event on the source, then inspect the destination directly in Outlook.
For Microsoft and Google together, follow the Google–Outlook setup guide. You can mix supported providers in the same account.
Check the destination your coworkers actually use
Seeing an event in a combined Outlook view doesn't prove that it exists on your work calendar. Hide the source calendar and open the destination copy. Confirm its time and busy status, then check the relevant scheduling or booking view where permitted.
Move the source event, cancel it, and verify both changes. For recurring meetings, test one occurrence too. Copies don't carry attendees or reminders, and changes made on a copy aren't sent back to its original.
If updates stop, inspect Activity and connection health. Reconnect the affected account when prompted; don't delete every rule to fix an expired connection. Provider notifications plus a 15-minute safety sweep drive automatic updates, without a fixed delivery guarantee. The troubleshooting guide explains how to separate permission failures from filters and delays.