Safari keeps crashing/freezing after install of El Capitan

Great to hear, Adam. 10.11.6 has gotten me optimistic enough to try Safari again after not using it in months. Thanks.

Just had my first Safari / Youtube 'crash' since 10.11.6 😟

I had a bunch of (non-Youtube) tabs open, opened a new tab, pasted a YT url and hit enter and bam - presented with a login screen. Back to FF as my dedicated YT browser I guess...

Login screen? That seems to be completely unrelated to this topic.

No - it is related. Let me be a bit more clear. When Safari went down - it crashed the GPU / window system. Hence being presented with a login screen. Here's the first log message when it crashed:

Aug 16 13:37:03 onosendai com.apple.WebKit.WebContent[52741]: HIToolbox: received notification of WindowServer event port death

This does sound different. This thread is related to a GUI lock-up when closing YouTube tabs or YouTube windows in Safari. This is the first I've heard of an issue when browsing to a YouTube URL. Also, I haven't seen any report of being returned to a login screen. The entire GUI was locking up.

Did you try the update yet, @palegreenghosts?

I haven't had any crashes. I am seeing some slowdowns, but I have no idea if they're related. The system regains speed after certain tasks end...usually involving scanning or video online video playback. I think this may be an unrelated 10.11.6 issue.

@Adam_F I did. I was holding off commenting until I had a better feeling for how it behaving but two weeks is probably enough.

It does appear to have addressed the tab closing/switching freezes. I tried to force the freeze, which was pretty easy to do in the past, and happily failed. After a few days I hesitantly made Safari my default browser while working and haven't had this freeze since. If it was a minor hardware bug, as some think, it appears to finally have a workaround and be undocumented (though I would hazard that documenting it would not be an option for Apple if there is a hardware issue).

I'm pretty delighted that it appears to finally have been addressed.

Besides that, I did have one or two issues with Safari that haven't repeated enough for me to feel listing them is warranted yet. So I wouldn't give too much weight to any of these just yet.

The major one happened when watching a YouTube video. It appeared to be a UI freeze but didn't involve closing or switching a tab. It was mid-playback and the image froze but the sound continued. Thinking it was just a playback issue I clicked the progress bar to no avail, then tried to open menus etc, and close Safari, which were all unresponsive. After about a minute, the UI jumped back to life and the video was moving again. I mention this because it has similar symptoms to the previous issue but a different cause. I can't say for certain if a particular action happened before the freeze. It's thankfully only happened once so I'll leave it at that for now.

I haven't seen, or at least noticed, an issue with an image freezing during playback, @PGG. I'll keep an eye out for that one.

Overall, I am happy to have most of the productivity lost by YouTube crashes back.

I'm still getting an intermittent Vimeo embed that displays garbled 'glitched' artwork as a teaser instead of the actual still image it should. This happened since I got the laptop, only with Vimeo embeds and only in Safari. The videos play fine and, if I don't play them, the intended still image returns to normal if I scroll away and scroll back.

It's an annoyance but it doesn't bring the computer to a standstill so I'll live with it. I always had a hunch that it was semi-related to the cause of the YouTube tab freezes. Still do.

Hi all. I may have had one freeze since 10.11.6, but after that no problem whatsoever. Glad to see that most of you didn't experience the freezes since the upgrade and looks like it may not have been a hardware issue.

Good to hear, Tok'ra! No more issues on this end either.

Glad to hear Tok'ra, and just to add that it doesn't 100% rule out a hardware issue. I would imagine if it's a relatively small hardware fault that's triggered by something uncommon that can be isolated, perhaps it's possible to circumvent and avoid triggering that something with a bypass-like function. Just a thought, though, and I doubt we'll ever find out either way.

I've had one more UI freeze the same as the Aug 29th post I mentioned above. I noticed the exact moment it happened and saw that it was as I moved the cursor over the progressbar of a YouTube video to show thumbnails. The UI seemed to ground to a halt as the sound continued normally. Clicks anywhere on the screen were unresponsive with the cursor that I could move. It came back to life every 5 seconds or so, spluttering segments of updated video. About 20 seconds later everything snapped back in sync and worked again. Unresponsive tabs taxing the CPU typically kick the fans in quite quick on my machine but they never kicked in once during this issue. I couldn't check Activity Monitor during the time but it felt like it wasn't a CPU strain. The ability to move the cursor around while everything else on the screen was frozen felt a lot like the symptoms of the previous tab closing/switching issue.

I've been using Safari as my main browser again since mid August. This has only happened twice and it didn't freeze the system to the point of requiring a hard reset. I'm happy enough to continue using Safari for now but posting this on the slight chance that it's useful as an update to any Apple engineers who were previously reading this thread and worked on the issue. I haven't had a single freeze from closing or switching a tab in Safari since the last update.

Though it doesn't freeze completely like it used to, there is still significant lag on certain types of youtube videos. One example would be the videos from Unbox Therapy channel. All of his videos lag for 5 seconds when you start playing, when you full screen, and when you close full screen etc.

I'm not able to recreate the lag that you're seeing, @Alwayserik. I was even at 4K. He's good, but I am wondering how that channel is at over 6 mil. subscribers (even if half of those are real, it seems strangely high) and nearly 2 mil. on a 1 day old video...that's probably another issue.

OK...back on topic...

Are you sure it's not an Internet issue? Your ISP could be doing all kinds of odd things.

@palegreenghosts - Good to hear your results. I haven't seen the very few nuances I had at first after the upgrade either. Maybe YouTube made some changes as well. I agree on the hardware comment. I'm not ruling a hardware issue out of the equation. I do wonder if there's anything else that's not running at 100%, but is just off our radar.

I also sometimes (very rarely) have slight lags when switching/closing code-heavy tabs with spinning beach ball, which goes away in couple secs, but no total freezes.