Cannot add invitees / guests in MacOS calendar events

Hello ormbol,

Welcome to Apple Support Communities!

If we understand your post correctly, you're unable to invite guests in Calendar on your Mac. We'd like to help!

Are all of your events synced to the Calandar on your MacBook Air?

Have you followed the steps below? 

Invite people

1. In the Calendar app  on your Mac, double-click or force click the event, then click Add Invitees or click next to any existing invitees. (You can also select an event, then use the Touch Bar.)

2. Enter each invitee’s name or email address, then press Return.

As you type a name or email address, Calendar tries to find a match in your Contacts and Mail apps, and on connected calendar servers. If you press Return before Calendar finds a match, or before you finish typing an email address, the invitee isn’t added.

After you enter two invitees, Calendar suggests the next invitee based on your previous interactions with people, such as who you often or recently invited together to the same meeting.

A symbol next to each invitee indicates the person’s status—for example, available, busy, or replied yes, no, or maybe. See Symbols used in Calendar.

3. If you see Check Availability below the last invitee, you can click it to see when invitees are free or busy. You only see Check Availability if your event is on a calendar service that tracks availability, such as CalDAV. 

You see invitees’ free and busy time in the Availability window. To find an event time with the fewest or no conflicts, you can:

• Move the event: Drag the event block.

• See another day: Click the arrows at the top of the window.

• See the next time all invitees are available: Click Next Available Time.

4. Click Send.

To remove an invitee, select the invitee, then press the Delete key.

If you regularly invite the same set of people to events, you can create a group for them in the Contacts app. Then, when you enter the name of the group, each group member is invited to the event.

If your calendar service provider allows group email addresses, you can enter them as invitees, and all the group members are invited.

Send an email or message to invitees

1. In the Calendar app  on your Mac, Control-click the event.

2. Choose Email All Participants or Message All Participants.

3. Enter text for your email or message, then send it.

Add invitees to Contacts

1. In the Calendar app  on your Mac, double-click or force click an event, then click Add Invitees or click next to any existing invitees. (You can also select an event, then use the Touch Bar.)

2. Hold the pointer over an invitee, then click the pop-up menu .

3. Choose Add to Contacts.

If you don’t see Add to Contacts, but you do see Show Contacts Card, the invitee is already in Contacts.

Invite people to events in Calendar on Mac

Let us know if you have any questions.

Thank you for using Apple Support Communities.

Take care!

ormbol,

Do you utilize other calendar accounts with this same Mac? If so, does the invitee lines appear there without issue? This will at least help us narrow it down for a specific account.

If it's happening with every account, you can try isolating it even further by going into safe mode and testing how it appears there: Start up your Mac in safe mode - Apple Support (HK)

Start up your Mac with Apple silicon in safe mode

1. On your Mac, choose Apple menu  > Shut Down.

Wait for your Mac to shut down completely. A Mac is completely shut down when the screen is black and any lights (including in the Touch Bar) are off.

2. Press and hold the power button on your Mac until “Loading startup options” appears.

3. Select a volume.

4. Press and hold the Shift key, then click Continue in Safe Mode.

The computer restarts automatically. When the login window appears, you should see “Safe Boot” in the menu bar.

Start up your Intel-based Mac in safe mode

1. Turn on or restart your Mac, then immediately press and hold the Shift key until you see the login window.

2. Log in to your Mac.

3. You might be asked to log in again.

4. On either the first or second login window, you should see “Safe Boot” in the menu bar.

Also, which version of macOS Monterey is currently on your Mac? Here's where to find it: Find out which macOS your Mac is using - Apple Support

Take care.