Third-party plugin "will damage your computer" errors on Mac

I am unable to print since yesterday from my iMac to a HP Printer that is connected to my home network. I get the following message:

hpPostScriptPDE.plugin will damage your computer

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Thanks, DiZoE:

This worked for me, after a week of frustration!

Many thanks,

Rudolf Hacker

No worries man, glad to help! 👍

After a couple of months of not being able to print, this worked for me. Thank you SO much!!!

DiZoE's solution worked for me after a couple of months of not being able to print. HUGE thanks to DiZoE !!!

Thank you, no worries, glad it worked out!

This fixed a weeks old problem straightaway! Thanks so much. I would have thought that Mac would update the printer drivers on OS update. Anyway, thanks again! :)

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Thank you so much! This fixed it for me. 😀

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Mr. Ti, this worked, bless you! I had run the system software update and was still getting the error messages. I then went and removed all the drivers using DiZoe's instructions, and also deleted them from my Printers & Scanners in sys prefs. i unplugged everything. then i downloaded the update from the Apple site. the installation took a while, be patient. i just was able to print a simple text file with my HP laser, for the first time since these idiots screwed it up last week.

Much obliged!!! Now we'll see if i can print from my all-in-one.

when i called both HP and Apple last week, they were blaming it on each other. The HP person told me i needed to buy a new HP laserjet. THANKS A LOT FOR THAT GREAT ADVICE, HP! yuch.

On Oct-28-2020, I tried various things in this thread without success. I got the hpPreProcessing.filter error, the hpPostScriptPDE.plugin error, and then the Matterhorn.framework error! I couldn't get the Mac catalina software update to refresh so that I could get a printer update.

Finally, what worked was a simpler process. I didn't need to delete the printers/hp folder or delete all my HP printers from the Printers & Scanners preferences. The problem only affected my laserjet, not my officejet. What i did was:

1. Install the latest version of HP Easy Start. I'm not sure this is necessary to get the latest drivers, but I found i should NOT re-install my laserjet from HP Easy Start. I did this 2 times and both times I got the Matterhorn-framework error. You might want to try just steps 2-6.
2. go to Preferences > Printers & Scanners
3. delete my laserjet by selecting it and clicking the "-" icon
4. Restart my mac
5. go to Preferences > Printers & Scanners
6. re-add the laserjet by clicking the "+" icon

I've had the same problem with my HP Photosmart Premium C310. I hadn't seen the Community posts but assumed this was something that slipped through the net when I upgraded to Catalina recently, so I located the HP Framework folder in my user library, zipped it, then deleted and restarted. On attempting to print again, HP prompted to reload Frameworks software, but same two files were flagged: pdftopdf.filter.app, ScanEventHandler. This time I just deleted them. This worked - I can print without these files it seems (I haven't yet tried using the scanner on the Photosmart). Thanks for all previous posts - I'll know where to look if further problems aren't fixed by Catalina updates.

Installing the update worked for me. I didn't have to do anything else. Thank you!