Vole’s concept is straightforward. Windows captures a snapshot of a user's active screen every few seconds and saves it to the disk. Users can then peruse these snapshots and, upon selecting one, are presented with options to interact with the content.

What could possibly go wrong?

The big cheeses at the Mozzarella Foundation and the makers of Firefox think that Vole is hanging on to rather too much data.

Mozilla's Chief Product Officer, Steve Teixeira, said: “From a browser's perspective, certain data ought to be preserved, while other data should not. Recall doesn't just archive browser history; it also saves data that users input into the browser, with only very rudimentary control over what is retained. Although the data is encrypted, this cache of information constitutes a new avenue of attack for cybercriminals and a fresh concern for privacy on shared computers.

He said that Vole was assuming the gatekeeper role, deciding which browsers will succeed or fail on Windows—naturally favouring Microsoft Edge.

Microsoft's Edge prevents users from recording specific websites and private browsing sessions by Recall. Other Chromium-based browsers can exclude private browsing sessions but cannot block sensitive sites (such as financial websites) from Recall.

"There is no guidance on how a non-Chromium based, third-party browser like Firefox can safeguard user privacy against Recall. Microsoft did not seek our collaboration on Recall. Still, we would have welcomed it, as it would have allowed us to work together to provide users with genuine control over their privacy, irrespective of their browser choice," he said.