​Microsoft now blocks the Windows 11 24H2 update on computers with USB scanners that support the eSCL protocol, a driverless scanning protocol that works over Ethernet, Wi-Fi, and USB connections.

The list of impacted devices includes standalone scanners and other devices with scan functionality, such as multi-function printers, fax machines, modems, and other network devices with eSCL protocol support.

The company confirmed the issue following widespread reports from affected customers, which started over a month ago on Microsoft's own community website, Reddit, and other online platforms.

"I've contacted the different vendors, both for the medical software it connects to and the scanner. According to Ricoh (the company that now owns fujitsu's scanner branch.) There's not currently a fix and they're working on it... that post was made on october 31st," one affected customer said on Reddit.

"Issue has happened on 5 of our computers that had an upgrade. We also built a 24H2 from a clean install and can replicate the problem. In the HP case, tried new drivers/new firmware and still nothing," another customer complained.

Caused by USB mode switch failures

As the company explained on Friday in a new Windows health release dashboard entry, this newly acknowledged issue is caused by the device not switching from eSCL to USB mode, which allows the scanner drivers to be matched.

"After installing Windows 11, version 24H2, you might experience issues discovering USB connected devices that support the eSCL (eScanner Communication Language) scan protocol," Microsoft said.

"You might observe that your device does not discover the USB connected peripheral and the device discovery does not complete."

The company has added a compatibility hold to block the Windows 11 24H2 update from being offered on systems with USB-connected eSCL scanners (the safeguard ID is 54762729).

Customers are advised not to manually update affected devices using the Media Creation Tool or the Windows 11 Installation Assistant until the issue is resolved.

Over the weekend, Microsoft added another Windows 11 24H2 safeguard hold on systems with Ubisoft games like Assassin's Creed, Star Wars Outlaws, and Avatar: Frontiers of Pandora because of crash, freeze, or audio issues caused by changes in the operating system.