Candidates see taken time slots: fixing interview scheduling double booking calendar sync

What this symptom means

An interview scheduling double booking calendar sync problem shows up when a candidate books a slot that already holds another meeting. ATS Mako calendar sync keeps availability accurate in both directions, so a slot booked elsewhere should not stay open for a candidate. When it does, the conflicting event is usually invisible to the sync. It may sit on a calendar that is not connected, be marked as free time, or be blocked by a permission setting.

Candidate self-scheduling works from a recruiter's real, current availability. That availability is only as accurate as the calendars it can read.

Why availability can be stale

• The conflicting event is marked Free instead of Busy, so it does not block time.
• The event lives on a different calendar, such as a personal or secondary calendar that is not connected.
• Calendar permissions changed, or a workplace administrator limits sharing.
• The wrong interviewer is assigned, so the booking link checks the wrong person's calendar.
• The conflict was added moments before the candidate booked, and the change had not reached the booking page yet.

Busy and free settings

Free events are the most common cause. In Google Calendar, a private event marked Free does not appear on your calendar, so nothing blocks that time. People with busy-only access see when you are busy but not event names or details. That is enough for scheduling, as long as the event is marked Busy.

Calendar permissions

For work or school Google accounts, your administrator decides whether you can share your calendar. On Outlook and Microsoft 365, an app can be denied access even after someone approved it, usually because the signed-in user lacks privileges for that calendar. Either way, the sync cannot see events it is not allowed to read.

Fix steps

1. 1 Find the conflicting event Open the interviewer's calendar and locate the event that overlapped the booked interview. Note which calendar it sits on.
2. 2 Set the event to Busy If the event is marked Free, change it to Busy. Do the same for recurring holds such as lunch, travel or focus time that should block interviews.
3. 3 Confirm the right calendar is connected Check that the calendar holding the conflict is the one connected to ATS Mako. If the interviewer keeps meetings on a second calendar, connect that calendar or move the events onto the connected one.
4. 4 Check sharing and permissions In Google Calendar, go to the right of the calendar and select Settings and sharing to review who can see busy times. If sharing is locked, ask your workspace administrator. For Outlook, see the Outlook sync guide linked below.
5. 5 Check interviewer assignment Make sure the right interviewers and hiring leaders are assigned. Availability works across every recruiter or interviewer on a requisition, so a missing or wrong assignment means the wrong calendars are checked.
6. 6 Move the affected interviews Use bulk event updates to retime or reschedule any double-booked interviews in one move. Candidates can also rebook against updated availability the same way they booked originally.

For connection problems on a specific provider, see fixing Google Calendar sync with interview scheduling or troubleshooting Outlook calendar sync.

How to confirm it worked

1. Add a test event marked Busy to the interviewer's connected calendar.
2. Wait a short time, then open the candidate booking link in a fresh browser window.
3. Confirm the test slot no longer shows as available.
4. Delete the test event and check that the slot reappears.

Prevention

• Ask interviewers to mark every real commitment as Busy, including personal holds during work hours.
• Keep interview-relevant meetings on the connected calendar.
• Review interviewer assignments when requisitions change hands.
• Set default start times and preset durations so open slots match when interviewers can actually meet.
• Re-check permissions after any account, password or admin policy change.

For more on how booking links, synced calendars and reminders fit together, see interview scheduling and calendar features or the guide to running candidate self-scheduling at scale.

When to contact support

Contact ATS Mako support if double-bookings continue after the test above passes, if a Busy event on a connected calendar never blocks time, or if several interviewers are affected at once. Include the interviewer's name, the calendar provider, the date and time of the conflict, and whether the event was created before or after the candidate booked.