"fax.backend will damage your computer."

HP have admitted to this being their fault. Long-serving forum member Kurt Lang posted this on Oct 24:

From sources familiar with the matter, 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 (Oct 23):

“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.”

HP supplied a new driver on Friday to fix the issue:

ftp://ftp.hp.com/pub/softlib/software12/HP_Quick_Start/osx/Installations/Essentials/hp-printer-essentials-S-5_14_8_4.pkg

However, that "fix" is producing this error for some users:

"Matterhorn.framework" will damage your computer…

If you're seeing that, try this fix. Go to System Preferences, select Printers and Scanners. Select your printer from the list then delete (-) it. Then add (+) your printer back and select the generic driver to use.

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

(2220 UTC 23 October 2020)

Open >System Preferences>Software Update      (Command R will reload and do a fresh check)

So I deleted this folder:

/Library/Printers/hp

And everything named: hp* or HP* in this location:

/Library/Printers/PPDs/Contents/Resources

Both requires root access.

I actually also deleted this file:

InstalledPrinters.plist

In this location:

/Library/Printers

Then i installed the printer as normally done, and everything works.

Hello, I had to get a new router and modem from my ISP Friday and when I tried to connect my printer something happened, I followed steps to uninstall my printer but now when I try to add a printer I get the fax.backend will damage your computer in a error box. I have an Epson printer not a HP so I have no idea how to get rid of this. I have the original printer installation CD, not sure if I should try to reinstall that way or not. I need to get rid of this error. Can you advise? I am running the latest software Big Sur 11.0.

Thanks for all the info very helpful. However how long does this totally uncalled for process take please? Im using printer ok but scanner won't work so I've been carrying on regardless. I realise I can't leave it like this forever but I've no idea how long it would take a no IT person like myself to do? Any timings would be gratefully received so I can arrange to take the week off!!!

Thanks Nita

We purchased a new Canon G6020 printer and got the same message when trying to connect with my Apple MacBook computer:

Message: "fax.backend"will damage your computer" How to resolve & get this new printer connected & usable?

Hi, I've sent a message earlier, but not seeing now so am resending:

We purchased a new Canon G6020 printer & I'm having the same difficulty connecting it with my MacBookPro > that is I'm getting the caution message saying 'fax.backend' will damage your computer. It will not allow me to 'add' the printer. What are the steps I should take to resolve this. I too need step-by-step instructions. Thank you:)

Since the macOS BIG SUR, my 2 printers won't work. Fax-Backend says that my printers "will damage my computer" .Since 2 days i try to put my printer back on, and Epson won't accept it? can you help me.

how did you even find that folder. I went to "open file" and typed in what you said and nothing came up.. I also don't know how to find that location "/Library/Printers/PPDs/Contents/Resources" nor do I know how to find / delete the file called "InstalledPrinters.plist" or how to find it in "/Library/Printers" ..... like where do I go / what do I do on my Mac to find this ? and how did you delete & re install it ? ugh im so confused on what to do . this is annoying

Just tried and this worked for me too. Highly suggest!

Worked for me too. Many thanks!

Steffen-Otto-Jensen Thanks, this worked perfectly.

Thank you so much! I have been unable to print for over a week since the update that caused the problem. I followed your steps and now I can print!!

Thanks everybody, I'm happy to have been helpfull.

I'm actually kind of surprised that there has been no (To my knowledge) solutions coming out of either Apple or HP.