Windows blocks atbridge (SmartScreen)

In short: Windows blocks atbridge as a routine precaution for newly released apps it hasn’t seen downloaded widely yet — not because it’s malware. Install from PowerShell (irm https://atbridge.ai/install.ps1 | iex), which isn’t blocked, or click More info → Run anyway on the SmartScreen dialog.

If you see the blue “Windows protected your PC” dialog, “unknown publisher”, or Windows Defender quarantines the file, that’s SmartScreen — the same caution Windows applies to any newer app it hasn’t seen many times yet.

Why this happens

Windows flags files downloaded from the internet with a hidden Mark-of-the-Web tag. When you run one, SmartScreen weighs how widely that app has already been downloaded and recognized. A newer, independently distributed app like atbridge hasn’t built up that recognition yet, so SmartScreen plays it safe and blocks the first launch by default — the same thing happens to plenty of small and new apps.

Note

This is a precaution, not a virus alert. Every atbridge download is verified during install by SHA-256 checksum and a minisign signature — if a single byte were tampered with, the installer refuses to run.

Fix it

Install script (easiest)

A PowerShell download never gets the Mark-of-the-Web, so SmartScreen doesn’t block it — and the script clears the flag for you as a safety net. Open PowerShell and run:

irm https://atbridge.ai/install.ps1 | iex

That’s the whole fix. It installs to %USERPROFILE%\.atbridge\bin\atbridge.exe, adds atbridge to your user PATH, and registers the Thunderbird bridge. No admin rights needed.

Click Run anyway

1. On the “Windows protected your PC” dialog, click More info (the small link under the message).

2. Click the Run anyway button that appears. Windows remembers your choice for this file.

Downloaded the file directly

If you downloaded the .exe in a browser, clear its Mark-of-the-Web. In PowerShell:

Unblock-File -Path "$env:USERPROFILE\.atbridge\bin\atbridge.exe"

Or from File Explorer: right-click the file → Properties → tick Unblock at the bottom of the General tab → OK.

If Defender quarantined it

If Windows Defender moved the file to quarantine, open Windows Security → Virus & threat protection → Protection history, find the atbridge entry, and choose Restore. Then re-run the install script above.

Caution

Don’t add atbridge to your antivirus exclusion list to get around this — it needs admin rights and broadly weakens your protection. The install script or Run anyway is all you need.

Verify

atbridge --version

A version string means Windows is letting atbridge run. If you closed and reopened your terminal and atbridge isn’t found yet, that’s just the PATH update — open a fresh PowerShell window.

Where to go next

• Install atbridge
• When activation fails
• When your AI can’t find anything

Faster: ask the community

For “how do I…” questions you will usually get a quicker answer — and help the next person with the same question — in Discord. Anything tied to your account, billing, or a bug is better as a support ticket, where we reply by email.