Live sync calendars from different companies

Hello Sir/Madam,

Good day!

Thanks for reaching out. I understand that you're a company admin managing an executive with multiple O365 email accounts across different companies (Company A and Company B). The issue is that appointments booked in one calendar (e.g., Company B) aren't visible in the other calendar (Company A), making it seem like the executive is available when they're actually busy.

To narrow down the issue, could you please confirm the following:

1. Are both companies using Office 365 for their email and calendar services?
2. Do you have administrative access to both Office 365 tenants?
3. Are there any specific privacy or security concerns regarding sharing calendar information between the two companies?

Regarding your question, live syncing of both calendars is not possible natively in O365, as it's designed to keep data separate and secure between different tenants. However, there are paid solutions like Microsoft Power Automate or third-party add-ins that can achieve this through workflows or syncing algorithms.

As for showing the executive as busy in both calendars, it's possible through the same paid solutions mentioned above. These solutions can update both calendars in real-time, reflecting the executive's busy status regardless of which company the original appointment is in.

If both companies are using Office 365, you can set up calendar sharing between the two tenants. This involves configuring the sharing settings in the Microsoft 365 admin center to allow users to share their calendars with people outside their organization. Here’s a straightforward solution:

Enable Calendar Sharing:

• Go to the Microsoft 365 admin center.
• Navigate to Settings > Org Settings.
• Select Calendar under the Services tab.
• Enable calendar sharing with external users who have Microsoft 365 or Exchange.

Share the Calendar:

• The executive can share his calendar from Company A with his account in Company B and vice versa.
• This will allow both calendars to reflect his availability accurately.

Microsoft Power Automate can help you achieve live, two-way calendar synchronization between different Office 365 accounts. This solution involves creating a flow that updates both calendars whenever an event is added, updated, or deleted in either calendar. Power Automate is available with a paid subscription, but it offers a robust and automated way to handle this synchronization.

Here are the detailed steps to set this up:

Sign in to Power Automate

• Go to Power Automate and sign in with your Office 365 credentials.

Create a New Flow:

• Click on Create in the left-hand menu.
• Select Automated cloud flow.

Set Up Triggers:

• Choose the trigger When an event is added, updated or deleted from the Office 365 Outlook connector.
• Select the calendar from Company A.

Add Actions for Each Trigger:

• For Added Events:
  • Add a new step and choose Create event (V4) from the Office 365 Outlook connector.
  • Select the calendar from Company B.
  • Map the event details from the trigger to the new event.
• For Updated Events:
  • Add a new step and choose Update event (V4).
  • Use the event ID from the trigger to find and update the corresponding event in Company B’s calendar.
• For Deleted Events:
  • Add a new step and choose Delete event (V4).
  • Use the event ID from the trigger to find and delete the corresponding event in Company B’s calendar.

Repeat for the Other Calendar:

• Create another flow with the same steps but reverse the calendars (i.e., trigger on Company B’s calendar and update Company A’s calendar).

Test the Flow:

• Add, update, and delete events in both calendars to ensure the flow works correctly and updates both calendars as expected

If you need help with this process, I recommend you post this query to the Find Answers | Microsoft Power Platform Community. Their technical experts there who will help automate this process using PowerShell.

Note*: Please understand that our initial reply may not always resolve the issue immediately. However, with your help and more detailed information, we can work together to find a solution.*

If this issue still persists after trying the following steps, it might be best to create a support request since you are an IT administrator  - Get Support - Microsoft 365 Admin |Microsoft Learn so you can get real time assistance. Our technical experts have access to advanced tools and resources that allow them to thoroughly investigate issues, collect logs, and perform remote sessions to configure your settings. This approach will provide the most effective solution. Rest assured, I will keep an eye on the progress and follow up to ensure a permanent solution office.com after you open a service request.

Thank you for your patience and cooperation. I look forward to working to resolve your issue once your service request is opened. Have a great day.

Best regards,

Eleni | Microsoft Community Moderator.