How to Fix Free/Busy not Available in Outlook Meeting Scheduling Assistant

When adding attendees to my meeting invitation, for some of the attendees, their free/busy status shows as “No Information” in the Scheduling Assistant.

Why is this and how can I make Outlook retrieve this information again for this attendee?

Free/Busy Information button

There could be several reasons why Outlook was unable to retrieve the Free/Busy status of an attendee.

Each of these reasons requires different solutions ranging from very easy to solve by yourself, to requiring your Exchange administrator to make server-side configuration changes.

Below you’ll find an overview of common reason reasons, things to check and solutions to get the Scheduling Assistant to show the Free/Busy information again for your attendees.

No free/busy information could be obtained for Professor Xavier. But why?

Quick Solution

Add Attendees button

With a bit of luck, you can easily solve this issue by removing the attendee and then adding it again via the Global Address List in the Outlook Address Book.

In this case, it is important that you do not select the attendee from the AutoComplete list when it makes a suggestion.

When you are on the Meeting tab and Outlook suggests the attendee when typing in the Required or Optional field, you can use the X on the right side to remove it.

This is the same method as removing an address from the AutoComplete list when addressing an email.

Optionally, you can reset your entire AutoComplete list via;

  • File-> Options-> Mail-> section: Send messages-> button: Empty Auto-Complete list

To select the attendee from the Outlook Address Book, simply click on the Required or Optional button.

When you are on the Scheduling Assistant tab, don’t add the attendee via the All Attendees list on the left but click on the Add Attendees command on the Ribbon instead.

The fact that this works is because somehow the cached AutoComplete entry has lost the relation to the Exchange object of the user.

Selecting the attendee from the Global Address List of your Address Book will make sure that all Exchange references for the user are correct again and the free/busy information can be retrieved.

Behaviour and limitations

Behavior & Limitations button

Other things to be aware of, and may quickly explain why you don’t see the Free/Busy information, are;

  • Verify that you are online with Outlook.
    This may sound obvious, but it is better to check anyway. Select your Inbox folder and look at the Status Bar on the bottom right. Here is should state “Connected” or “Online”. When it shows “Working Offline” or “Connecting”, the lookup will fail.
  • Make sure you are in the Calendar of your Exchange account.
    Free/busy lookup doesn’t work for Calendars belonging to POP3 and IMAP accounts.
  • Check whether the attendee is part of your organization.
    By default, free/busy only works for internal attendees. Adding someone from another company, only works when your administrator has configured a federation trust. This exception is explained in more detail later in the guide (Check 3).
  • Expand your distribution lists or Microsoft 365 Groups.
    You’ll need the individual members of the group to collect the free/busy information.
  • You’re having “too many” attendees for your meeting.
    There is a limit to the amount of attendees Outlook can show free/busy info for. Unfortunately, this limit isn’t published and also has to do with how long it takes for the information to be retrieved. However, I had no issues with adding over 500 attendees to a single meeting; Outlook collected the free/busy information in batches and completed that for all attendees within 3 minutes.

Ref: Free/Busy information not available in Meeting Scheduling Assistant –