N2See: Control over windows on external displays

N2See stands for "Nothing to See" and describes a specific problem that regularly occurs in macOS. As soon as an external monitor or projector is connected, the system automatically distributes open windows to the new screen. What is intended as a convenience feature can quickly become annoying. Suddenly, calendars, emails, or other sensitive content appear where they don't belong. This is precisely where N2See comes in.

For years, macOS has exhibited a behavior that is difficult to reliably control. Open apps are sometimes unexpectedly moved when an external display is connected. This poses a real privacy risk, especially during presentations or spontaneous screen switching. N2See was developed to specifically minimize this risk without disrupting workflows or introducing additional complexity.

What is N2See?

N2See is a free and open-source app for macOS. It prevents open windows from being unintentionally displayed on external monitors or projectors. The app runs continuously in the background and intervenes automatically as soon as a new screen is connected.

This isn't about blocking presentations, but about control. Content stays where it belongs and isn't moved to other people's or public displays without permission.

The macOS problem with external displays

macOS often treats newly connected displays as an extension of the existing workspace. In practice, this means that windows are redistributed. Which app ends up on which screen is often unpredictable.

This can be critical in presentation situations. Calendars with appointments, emails, messages, or other confidential information are, in the worst case, immediately visible to everyone. N2See addresses this issue directly and consistently interrupts this behavior.

How N2See works

As soon as an external screen or projector is connected, N2See reacts automatically:

The new screen will dim immediately.
All open windows will be moved back to the internal laptop screen.
The process runs in the background and requires hardly any system resources.

This process happens so quickly that content is usually never even visible. N2See doesn't replace presentation software, but rather ensures that no unwanted content appears before an external display is actually used.

Features and Highlights

N2See deliberately focuses on a few, clearly defined functions:

Runs unobtrusively and resource-efficiently in the menu bar
It immediately detects when a new screen is connected.
Automation is possible for each display individually, for example, only for unknown displays.
Optional rules per app, for example only for calendars or specific programs
Setup takes less than a minute
Requires macOS 13 or later

By combining display and app rules, N2See's behavior can be adapted to different workflows without having to make complicated settings.

Operation and setup

After installation, N2See appears as a small icon in the macOS menu bar. All relevant settings can be accessed from there. The configuration is intentionally simple and can be completed in a very short time.

Once set up, the app runs independently in the background. No further intervention is necessary, and there are no visible interruptions to the workflow.

N2See: More control over external displays

N2See solves a specific and common problem on macOS. The app reliably prevents sensitive content from being unintentionally displayed when external displays are connected. It does so unobtrusively, quickly, and with low resource usage.

Free, open-source, and streamlined, N2See integrates seamlessly into everyday macOS use. For those who regularly work with projectors or external monitors, N2See offers a simple way to maintain control over visible content – download it from the Mac App Store! (Image: N2See – Nothing to See)