Signal has implemented a new privacy feature in its Windows app to prevent Microsoft’s AI-powered Recall feature from capturing screenshots of private conversations. The “screen security” feature, now enabled by default on all Windows 11 devices, sets a Digital Rights Management (DRM) flag on Signal’s app windows to block content capture by Recall and other Windows applications.

Microsoft’s Recall, introduced in May 2024, continuously takes screenshots of active windows every few seconds, analyzing them to create a searchable database. Security experts immediately flagged it as a privacy risk that could potentially be exploited by attackers to steal sensitive data.

“Although Microsoft made several adjustments over the past twelve months in response to critical feedback, the revamped version of Recall still places any content that’s displayed within privacy-preserving apps like Signal at risk,” explained Signal developer Joshua Lund in a blog post. “Microsoft has simply given us no other option.”

While Microsoft has implemented various safeguards for Recall—making it opt-in, requiring Windows Hello authentication, filtering sensitive information, and allowing users to exclude certain apps—Signal determined these measures were insufficient to protect user privacy.

The screen security feature may cause compatibility issues with screen readers. Users who need to disable it can do so through Signal Settings > Privacy > Screen security, though they’ll receive a warning that Windows can then capture screenshots of their Signal conversations.

Lund emphasized that this solution isn’t ideal: “Apps like Signal shouldn’t have to implement ‘one weird trick’ in order to maintain the privacy and integrity of their services without proper developer tools. People who care about privacy shouldn’t be forced to sacrifice accessibility upon the altar of AI aspirations either.”

The protection only works on Windows devices and won’t prevent screenshots taken by others using screen readers on macOS or Linux systems.