Updated Many Mac users today found, to their surprise, they are unable to print to their HP Inc printers.

This is due to a code-signing snafu affecting macOS Catalina (version 10.15) and Mojave (10.14), specifically. HP's printer driver software is cryptographically signed with a certificate that macOS uses to determine whether the application is legit and can be trusted. However, that certificate was today revoked through an XProtect update, causing the software to be rejected by Macs.

XProtect is the mechanism Apple uses to inform Macs to no longer trust and run certain programs, and it does this by revoking their code-signing certificates. There is no central database of certs cancelled by XProtect, there's one for each OS version it seems, and Catalina and Mojave were selected in particular. Apple chose to revoke the HP driver cert, or perhaps was asked to do so by HP.

'No questions asked' Windows code cert slingers 'fuel trade' in digitally signed malware

Select the printer that you’ve connected from the list of available devices. Right-click the device and select Update driver or Update driver software. Click Search automatically for updated driver software. Follow the on-screen instructions to install the updated driver. Restart your computer. After over a year with having two HP printers in use, this morning, after startup of my Mac, I started getting this same pop-up. In searching for a cause, I saw where to look in the /Library/LaunchAgents folder and indeed this file was put there yesterday, at 10:00 AM: com.hp.devicemonitor.plist. Add your printer with different settings. On your Mac, choose Apple menu System Preferences, then click Printers & Scanners. Select your printer in the list, then click the Remove button. Click the Add button, and if a pop-up menu appears, choose Add Printer or Scanner. A dialog appears listing any IP, shared, and Open Directory printers on.

In any case, HP's driver software no longer works on those two particular operating system flavors. Users are told when trying to print, for instance, that HP's application 'will damage your computer,' and are given the option to run it anyway or send it to the trash. Trying to continue just loops you back round to the error message, with no work done. Punters are also encouraged to report this 'malware' to Apple.

Unofficial workarounds for now include using AirPrint to an HP printer, or uninstalling the HP software and using a generic PostScript driver.

A Reg reader who tipped us off about the blunder told us he was able to jerry rig some IPP connectivity to get an older device to print: 'We had a handful of printers where macOS would print into the ether. Windows had no problem. I found some IPP trickery on macOS Catalina worked on an older HP4650.'

We had a handful of printers where macOS would print into the ether. Windows had no problem

Complaints from punters are building up on the Apple and HP support forums.

'Trying to open Printer Utility on MacOS 10.15.7 and I get a crash dump every time saying 'Code Signature Invalid' for the binary /Library/Printers/hp/Utilities/HP Utility.app/Contents/MacOS/HP Utility,' said one netizen.

'Yes, my Deskjet F4140 abruptly stopped working with both my Mac mini desktop AND my partner's AirBook,' complained another. 'The AirBook keeps insisting it's malware (it's not), while my desktop says the certificate has expired. Suddenly, HP and Apple are NOT playing well together! I've redownloaded and reinstalled the printer software TWICE now but nothing has changed, just the same message about HP Utility now missing. Our jobs depend on this printer, HP.'

Thomas Reed, director of Mac and mobile at Malwarebytes, tweeted to say his users were up in arms at the tech breakdown: 'We're seeing a significant influx of support cases where users are seeing macOS identify what appear to be legit processes as malware.'

Mac blogger Howard Oakley has some more background, here. 'You’re seeing that [error] message because macOS is checking the signature on your HP printer software, and being told that its signing certificate has been revoked,' he observed.

Amazon's Music desktop app is also, weirdly enough, no longer working, either, it's reported.

Spokespeople for HP and Amazon were not available for immediate comment. Apple declined to comment. ®

Updated to add

The Register understands from sources familiar with the matter that HP Inc asked Apple to revoke its printer driver code-signing certificates. It appears this request backfired as it left users unable to print. A HP Inc spokesperson told us on Friday night:

We unintentionally revoked credentials on some older versions of Mac drivers. This caused a temporary disruption for those customers and we are working with Apple to restore the drivers. In the meantime, we recommend users experiencing this problem to uninstall the HP driver and use the native AirPrint driver to print to their printer.

Mini Mac User wrote:

After the recent Catalina OS 10.15.7 download my HP printer was axed. But thankfully with the help of DiZoe I got the printer back up via his great instructions.

Today I tried to scan and another Klingon message was received: 'Scanner reported an error. The operation couldn't be completed. com.apple.imagecapture error704.' My scanner is part of my HP F1480 Deskjet printer

Is there anyone out there from The Borg who has an idea how I can use my scanner again? Thanks in advance for your help.

Open >System Preferences>Software Update

Update: HP Printer Software 5.1 should now be becoming available through Software Update to fix this issue.

Hp Printer Updates For Mac Catalina

(2220 UTC 23 October 2020)

or Apple direct download:

How To Update Macos Catalina

If you still have an issue, and listed as AirPrint printer, delete the existing printer in

> System Preferences> Printers & Scanners, and add it again, select AirPrint.

Hp Printer For Macos Catalina

Hp Printer Updates For Mac Catalina

Connect an AirPrint printer to a Wi-Fi network - Apple Support.

about AirPrint

What Is The Latest Update For Macos Catalina

How Do I Update My Hp Printer Software On My Mac

you can also try reset print system if necessary:

If you can't print from your Mac or iOS device - Apple Support

If you are still at a loss: https://123.hp.com/us/en/

Nov 5, 2020 2:24 PM