Outlook has no "Send availability" button: why, and what to do instead

The problem

You read that Outlook can insert your free times into an email. You open a new message, look for the button, and it is not there. Or a colleague has it and you do not. Or it appears on your laptop and vanishes on your phone.

This is a version and licensing question, not a bug. Here is how to work out which case you are in, and what to do in each one.

Where the feature lives

The availability options in Microsoft 365 are spread across different Outlook experiences, and they are not the same feature.

Outlook on the web and new Outlook for Windows are the modern experience and the place where availability sharing is most likely to be present. When it is available, you open a new message, find the scheduling options in the compose window, pick times from a grid, and insert them. The recipient gets clickable times that book the meeting when clicked.

Classic Outlook for Windows has an older, different thing: Insert Calendar, which drops a block of your free/busy into the message body. It does not produce clickable booking times. The recipient just sees when you are free and replies with a preference.

Outlook mobile is the most common surprise. The native iOS and Android apps do not surface the same compose-time scheduling options, so people who set something up on a laptop find it missing on a phone.

Outlook for Mac sits somewhere in between depending on build.

So the first question is not "why is my button missing" but "which Outlook am I actually in".

The four usual reasons it is not there

1. You are signed in with a personal account. The availability and personal booking features are work-and-school features. A personal outlook.com or hotmail.com address does not get them.

2. Your licence does not include it. Availability sharing in Outlook is built on Microsoft's personal booking page infrastructure, which depends on your Microsoft 365 plan. Some plans include it, some do not. This is why the button exists in Microsoft's own demo videos and not in your window.

3. Your admin has not enabled it. Even where licensing allows it, tenants can leave personal booking pages switched off. Nothing you change in Outlook settings will bring the button back. Ask your admin whether personal booking pages are enabled for your account.

4. You are in the wrong Outlook. See above. Classic desktop and mobile behave differently from Outlook on the web.

Before you file a ticket, sign in at outlook.office.com with your work account and check there. If it works on the web but not on your desktop app, it is a version issue, not an account issue.

What to do instead

Option 1: Scheduling Poll

Already in Outlook, nothing to install, works cross-tenant. You propose times, recipients vote, and Outlook books the winner. Use this when you are genuinely happy to let a group decide. It is the best free option and we will say so.

The catch is tone. A poll makes the recipient do work, and when you are the vendor, the recruiter, or the assistant writing on someone's behalf, sometimes the expected answer is simply a list of times.

Option 2: Scheduling Assistant, typed by hand

Open the Scheduling Assistant, read the grid, type the times into your email. Free, universal, and works in every Outlook version ever shipped. It is also slow, and it is where time zone mistakes come from. If you do this twice a week, it is fine. If you do it eight times a day, it is a real cost.

Option 3: Generate the list and paste it

This is what OpenSlot does, and it is deliberately narrow: it produces a clean list of times you can send.

• Works as a web app and as an Outlook add-in for Windows, Mac, and Outlook on the web. The add-in inserts the list into the email you are already writing.
• "Just me" for your own availability, "Me + others" to merge colleagues' calendars into times when everyone is free.
• Any time zone, a window of up to 60 days on Pro (seven on the free plan), working hours that default to 8 to 5, a minimum slot length, weekends on or off, and an option to treat tentative as busy.
• Settings roam across devices, so the web app and the add-in behave the same way.

It reads Microsoft 365 free/busy read-only through delegated Graph scopes. It uses only the availability and stores no calendar data. Availability is computed live each time you generate a list.

The output is text in your email. No page for the recipient to visit and nothing for them to install; on the free plan and during the trial the list ends with one short line linking to OpenSlot. They read the times and reply.

Which one to pick

• Internal meeting, everyone in your tenant: use the Scheduling Assistant and just send the invite.
• Group that should vote: Scheduling Poll.
• Your Outlook has availability sharing and your recipients like clicking times: use it. It is free and it books the meeting for you.
• Your Outlook does not have it, or your recipients want plain times in the email, or you need several colleagues merged: that is the gap OpenSlot fills.

Cost, so you can decide quickly

The Free plan covers you plus one other person on a 7-day window. Every new account starts with a 14-day Pro trial, no card required. Pro is $7 per user per month or $72 a year. Team starts at $5 per user per month, five-seat minimum, with volume tiers. Billing is self-serve through Stripe.

The add-in is listed on Microsoft Marketplace, published by OpenSlot LLC, a Microsoft verified publisher based in Kentucky. If you get stuck, the help pages or support@useopenslot.com will do.

One honest caveat: if your tenant blocks third-party apps, that decision outranks anything on this page. In that case Scheduling Poll and the Scheduling Assistant are your tools, and they are better than nothing.