Spoke with Applecare, and they said it is the fault of the printer companies, as they need to update their drivers better. Applecare said that all third party companies get Beta versions of any new OS software prior to the software release to the public, and it is up to them to update their own drivers so that they work with the new OS after it gets released to the public. On the flip side, Brother Tech Support said that if the printer works with Microsoft Word, and prints test pages correctly, and works with Google Chrome, that it is the fault of Apple, so both sides blame the other, and the consumer gets screwed in the middle. I will note that Messages program has errors in it as well after upgrade (can't block contacts from texting) and that an Apple program with defects running on Apple OS. Hard to blame 3rd party for that. Plus, the fact that the the filter failed error is only coming up on Apple programs (Safari, Preview, Mail) after updating Apple OS Mojave (and not on Chrome or Word or Photoshop), leads me to ultimately deduce that Apple is most likely the primary culprit. No one I know likes to update software given all the errors that occur as a result, and most wouldn't if they could get by without it. However, Apple forces you to update OS, by both software and hardware requirements. I agree with the comments below that while Apple Design has improved over the years, the actual reliability of the product is declining. My MacBook 12 (2015) looks and feels nice, but has been nothing but problems. I was denied AppleCare warranty purchase on a technicality, need a keyboard replacement, and have had to reformat the hard drive twice already at the instruction of Apple. My 3 year old iPhone 6s plus has already had a battery replacement. In the last two years, I have had to call Apple at least 20 times (and I am a skilled computer user compared to the average person, and look up everything I can before calling Tech Support). At least their phone support is free. There is that. Sadly, it is still the best computer on the market, and has a price tag to match. Perhaps Elon Musk should start building computers too!