Protect your team's focus hours with a ten-minute calendar lockdown
Set Google Calendar to known senders only, delete suspicious invites, and give your team a short rule to protect focus blocks.
Auto-landing invites are standing meetings you never approved
A full calendar is a ledger of borrowed time. Every recurring invite that nobody reviews takes hours from the work that moves. The problem is that some meetings arrive before anyone has decided to hold them.
For a manager, the cost is easy to see. If a team of eight loses one hour a day to unreviewed invites, that is eight hours gone before the first real task starts. Multiply that across a week, and the meeting load becomes a standing debt on deep work.
Calendar spam has become a security issue as well as a focus issue. Sublime Security projected that ICS calendar phishing, an attack that abuses calendar files, would grow by about 33,000% from May through September 2026. The firm reported that fake calendar-invite malware attacks jumped 282% in June, then 338% in July, and 1,216% in August, and it expected a 2,852% jump in September.
The calendar lockdown settings protect focus blocks
The fix is a short, repeatable lockdown. You do not need to audit every past invite. You need to change the default so unknown invitations stop landing as events, and you need a simple rule for what to do when one appears.
The lockdown is easier than it sounds. You are not asking the team to become security analysts. You are asking them to stop treating every invite as a default yes.
- Open Google Calendar and find the Add invitations to my calendar setting.
- Set Add invitations to my calendar to Only if the sender is known, which covers contacts, organization-domain senders, and people you have emailed before. The other choice keeps unknown invitations from becoming events until you answer through mail.
- Delete suspicious invites instead of clicking, RSVPing, or declining them, because rejecting an invite can signal to an attacker that the address is live and active. Done looks like the invite is gone and the email is archived or deleted.
- Google started adding a native block button to Google Calendar in August 2026, and the rollout continued reaching users through September 2026. If you see it, use it to block a sender.
- Tell your team to use the same rule: delete unknown invites, do not RSVP, and protect the same focus blocks.
The warning is simple: do not treat a suspicious invite as a normal meeting request. If the sender is unknown, the safest action is deletion, not a reply of any kind.
Recurring invites need a cancellation date
Lockdown stops new unknown invites. It does not clean the calendar that already exists. A manager should review recurring invites in the same short pass, but the review is about value, not security. Ask whether the meeting still has a purpose, a clear owner, and a reason to repeat. If it does not, send a short cancellation note that names the change and offers a lighter alternative.
The cancellation note should be direct. Say the recurring meeting is being paused, explain the reason in a sentence, and ask for a specific alternative if the sender still needs time. A good alternative is a shared document, a short written update, or a single meeting with a clear agenda. This keeps the relationship intact while removing the recurring block from the calendar. A paused meeting is easier to restart than a meeting that has become routine.
Do not cancel in a way that leaves the sender guessing. A blunt but useful message says what is changing, why it is changing, and what the sender should do next. If the meeting was created by a tool, a department, or a legacy process, name the process and ask for the owner.
The rule sticks when the team shares the same default
Individual settings protect one calendar. Team rules protect the hours that matter. In August 2026, Google let Workspace administrators enforce the Add invitations setting across corporate domains. If a manager can use that option, use it.
Put the rule in the team's onboarding notes, and review the calendar regularly. The review should answer a question: which recurring invites still have a clear purpose? If the answer is no, cancel the invite and protect the block.