# Windows blocked SellyPOS: Smart App Control

> Why Windows 11 Smart App Control may block the SellyPOS installer, your choices, and what turning that setting off means for your computer.

Source: https://sellypos.com/help/troubleshooting/windows-smart-app-control/
Updated: 2026-11-03

Windows 11 has a protection called Smart App Control. SellyPOS is new and its installer is not yet signed with a company certificate, so Smart App Control may stop it from running. This page explains what you may see, what the setting does, and the choices you have.

## What you may see

After you run the SellyPOS installer, Windows may block it. You may see a message saying the app was blocked. It may mention Smart App Control or protecting your device, and it has no **Run anyway** button.

SellyPOS may also run with no message at all. We cannot promise either way.

## What Smart App Control is

Smart App Control is a Windows 11 feature. In most cases it turns itself on to protect you from untrusted or malicious apps. It is often on in a computer that was set up as new recently. It turns itself off for some people, for example on a work-managed device, in developer mode, or in Windows in S mode. It may also be off because someone turned it off.

When you run an app, Smart App Control checks whether Microsoft's cloud security service can make a confident prediction about that app. If the service believes the app is safe, the app runs. If it believes the app is malicious or unwanted, it is blocked. If the service cannot make a confident prediction, Smart App Control checks for a valid signature. A valid signature lets the app run. An app with no signature is treated as untrusted and blocked.

## Why it can block SellyPOS today

SellyPOS is new, and its installer is not yet signed with a code-signing certificate. On a computer where Smart App Control is on, that means it may be blocked.

Microsoft says there is currently no way to let one app through Smart App Control. You can turn Smart App Control off, or the app's developer can sign the app with a valid certificate. Getting a certificate is on our list.

## Your choices

You can turn Smart App Control off on this computer, or you can keep it on. If you keep it on, you can use a computer where it is off, or message us and wait for a signed version of SellyPOS.

If you decide to turn it off, follow these steps.

1. Open **Windows Security**, then choose **App & browser control**, then **Smart App Control settings**.
2. Choose **Off**. The menu names can differ a little between Windows versions.
3. Run the SellyPOS installer again, then continue with [installing SellyPOS](/help/getting-started/install-sellypos/).

> **Before you turn it off**
>

Turning off Smart App Control lowers one layer of protection on this computer, so the choice is yours. We do not ask anyone to do it casually. It does not turn off Microsoft Defender antivirus or the firewall. Those are separate settings.

After the installer has finished, you may be able to turn Smart App Control back on. Microsoft says recent Windows updates allow this without reinstalling Windows, but the change arrives gradually. On older versions of Windows, turning it back on may need Windows to be reset or reinstalled. So look at the Smart App Control page first. If you are not sure you could switch it on again later, ask us or an IT person before you turn it off. Do not count on being able to switch it back on.

## When this will change

A valid signature is one of the things Smart App Control looks for. When we sign SellyPOS with a code-signing certificate, we will update this page. We do not have a date for that yet. Until then, use one of the choices above.

Questions? [Message Selly Systems on WhatsApp](/contact/) and we will help you. If your browser warned you before the download, read [why your browser warns about the SellyPOS download](/help/troubleshooting/download-warning-in-your-browser/).