macOS Sonoma 14.3 - Safari and Outlook Broken, how to fix it without "Erase Mac"?

Well 14.4 lasted a day. I held my breath and updated to 14.4.1, and also updated Outlook to Version 16.83.2 (24032318) today (26 March). So far, Outlook is working fine - I've even done an email merge with Word and Excel, and Apple Mail is also behaving itself. I'm running a reconditioned macBook Pro 16" M1 chip if that helps.

Hmm. I've just (25 Mar 2024) updated to Sonoma 14.4 and the Outlook problem has gone away, ie it functions again ... for now. But it did take about 10-15 seconds to Quit the first occasion I opened it. Btw I've never had the Safari problem.

You said “your customers.” So you also have the problem on your own Macs?

Anything else installed across all of the Macs, especially any sort of internet security software?

Is there anything in the Proxy settings? I’m under the impression other browsers use their own proxy settings.

Maybe not erase, but just reinstall macOS.

Everything I think might be related doesn’t seem to be.

I don’t know if EtreCheck would help you identify what is installed. You eliminated most culprits with Safe Mode. I know it is licensed free for individual use, but never looked at the license for your case. I can’t imagine you finding something on all four unless your business services some specific subset of users.

It's 4 days since this original post (OP), but I may have some additional information that narrows the search for what's causing these symptoms. How did I come across this post? 2 days ago I erased/initialized a MacBook Pro internal disk and fresh installed (via Internet) Sonoma (and it turned out to be 14.3). Over the last 2 days I've been using this fresh new system noticing odd Safari behaviors (under my Sonoma 14.3, Safari shows as version 17.3). Those behaviors that sounded exactly like the OP described here: blank pages, and some sophisticated pages (multiple examples) that paint a screen full, but scrolling down results in either total blank or very screwed up formatting. I have Chrome and I almost always test with it to confirm/deny any Safari problems and Chrome behaves correctly when accessing these same "blank white" pages or what I called sophisticated websites above. (I do not use Outlook so can't comment on that aspect).

So I see Sonoma 14.3 (and maybe Safari 17.3) as common ground to our problems. Any other similar findings or behaviors from those following this discussion?

No idea about the problem specifically, but have you eliminated Outlook completely to rule it out?

I don’t use Outlook, but I don’t have any of those problems on two Macs.

Have you disabled the IP address hiding in Safari and macOS to see if it is related?

I must add to my post above. I may have spoke too soon and have noticed two things with my fresh Sonoma 14.3 system. As I went on looking for similar issues I noticed that there has been a history of odd Safari behaviors since Sonoma was first released back in ... Oct 2023. Several of them reported it took a few minutes of use (20min?, etc) for Safari to start screwing up. I just realized that matches my symptoms too. I can go back to some of these sophisticated pages and Safari renders them fine and correctly (I probably restarted Safari in the interim). So that weakens the case for finger pointing at Safari but doesn't exonerate it. My seeing Chrome having no problems rendering the same page may have been more of "a fresh browser" (any browser) rendering the page soon after starting the browser. I'm still researching and refining my symptom description.