Monday, May 24, 2021

Remaining Issues in Big Sur

I updated my main Mac to Big Sur a month and a half ago, so I’ve been using macOS 11.2.3 through 11.3.1. Unfortunately, I’m not sure that it fixes any of the Catalina issues that I mentioned, and it introduces a variety of new ones:

See also: Big Sur 11.3 bug tracker, Multiple Issues including Kernel Panics.


Update (2021-05-24): Josh Centers:

Photos just straight up corrupted a photo in iCloud the other day. That corruption synced between devices. Thankfully I was able to restore it, but geez.

Update (2021-05-25): Rui Carmo:

I’ve only experienced some of these issues, but the interesting bit is that I have heard about most of them through complaints from my friends, so it seems pretty comprehensive.

I do have to wonder why this is still the case this far into the 11.x cycle, since Big Sur really ought to be a lot less buggy than Catalina.

See also: Hacker News, Twitter.

Update (2021-06-02): Jesse Squires:

This is the longest I have ever waited to upgrade macOS. It feels weird, considering WWDC is next week where we will see what is next for macOS. Big Sur still feels new to me, and announcing the next major release already feels too soon. I was avoiding Big Sur based on various reports about bugs and instability. There were not any ‘killer’ features I was eager to have, thus the main reason I upgraded was because Xcode 12.5 required it.


Michael Tsai and Howard Oakley have diligently documented all sorts of issues with Big Sur. I have experienced many of them. Most bugs are small, or they are “fixed” temporarily with a reboot. The last six or so years of macOS have felt like “death by 1,000 cuts” — I would love to see that change next week at WWDC.


Speaking of trash — Mac Catalyst apps. They are just terrible.

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Fire Federighi

I have to confirm most od those nasty bugs

I don't know what you do with your Mac, but for another bit of anecdotal evidence, I don't experience nearly the bugs you do. I only reboot for software updates, I've got Time Machine, SuperDuper!, and Arq running backups, DEVONthink and Pastebot, Xcode, Docker, etc…

The biggest Big Sur issue I have is Safari sometimes beachballs for 2-3 seconds when opening a tab. That's very annoying, but doesn't seem like much compared to the list above. Probably an issue in one of the extensions I've got.

@Martin, Whoa, whoa! And then what? Bring Forstall back? :) Unfortunately that's not possible without Apple posting significant loses. And even then I doubt it will happen - they will just double down on "services" revenue.

Issues I have experienced with macOS Big Sur (M1 MacBook Pro 16GB/1TB) are mostly performance related:

- WindowServer constantly at 50% CPU usage (disabled all transparency and motion effects, using simple wallpaper, the only time it sits around 4% is if literally nothing is open and the Mac is not in use)

- WindowServer consistently uses 7GB RAM (currently have Safari with Ghostery content blocker, Terminal, TextEdit, Messages open, is that too much for M1 or Big Sur?)

- Typing in Safari forms (like this) and TextEdit has a ~0.5 second delay for each character typed, feels like typing into a dialup BBS

- Pulling down and navigating menus in Safari is sluggish

- kernel_task writes ~120GB to SSD per day, smartctl shows 51.1 TB of writes to the disk since purchase.

- Switching between TextEdit and anything (or vice versa) causes an inexplicable multiple second delay

- Many High Contrast UI elements are broken

- Finder does not update file/directory contents in a timely manner, sometimes several minutes. If I need quick access to a newly saved or modified file I close and re-open the same folder and it usually appears after a moment.

The performance stuff starts right away on a fresh reboot, and have always existed on this Mac.

A colleague suggested that many of my performance issues could be caused by macOS Big Sur phoning home with trustd to do anything, and because my local ISP maxes out about 24mbps (but is more like 3mbps in usage) that everything is slow. I haven't tried blocking trustd yet, mostly because I am not sure the broader consequences of that are worth it.

Overall, macOS Big Sur kind of reminds me of Mac OS X 10.0, if anyone else remembers that first release, which was basically an incredibly slow public beta with a very garish UI that was nearly unusable until 10.1 came along.

I see a lot of people raving about the m1 Mac performance, but mine feels about as fast as a 2018 MacBook Air that it replaced. The old trusty 2015 MacBook Pro is much quicker (running Mojave) with a fraction the resource use.

Anyway, I'm certainly not impressed by any of this performance. I don't know if it's entirely Big Sur, but what a resource hog either way.

>It’s now possible to remove the Spotlight menu, but I don’t see a way to get it back.

This is arguably one of the things that's nicer about Big Sur: this kind of stuff is now all under System Preferences, Dock & Menu Bar (in this case, Spotlight, Show in Menu Bar).

@Sören Forgot about that, thanks. I do think it’s odd that it’s only there, whereas e.g. the Siri, Time Machine, and some other icons are also available from their respective panes of System Preferences.

But other than that, how was the update?

@ Michael: yeah. Seems they've removed the setting from e.g. Date & Time, but some panes still have the checkbox.

Wow, I don't have almost any of these. Possibly of note, I have a 2015 27" iMac, and stayed on Mojave until 11.2, I never installed Catalina or first Big Sur. I suspect that's the cause of most woes, burn your system to the ground and reinstall Big Sur and it may work better?

WindowServer goes crazy sometimes; not just when I wave the mouse around which comically brings it over 100%, but even apparently doing nothing it'll take off and the fans will start up. Closing a window somewhere usually fixes it?

Safari likewise goes from normal 100% CPU, often in a background window.

The audio switcher thinking media playing in Mastodon has higher priority than iTunes for using media control buttons is INFURIATING. I shout profanities that'd make a normal person sterile and then have to use the mouse. To control media. So mad.

Finder is sometimes as much as 10 seconds behind reality on rapidly-changing contents. Mostly it's OK. Save dialogs have never gone anywhere but where they say, but it's still obnoxious 20 years after 10.0 that the default in most apps is last-used folder, not the folder containing my document.

Spotlight indexing is terrible, verging on broken. I'm about ready to reset it and start it indexing again, because half the time it shows no results, the other half it gives wrong results. My screwing around with external drives may be partially or wholly responsible for this.

Notification clear is harder to hit and I can't tell I have old notifications sitting in there unless I click on it.

Nothing has crashed at all. Mail is worse-designed, but I don't see any technical problems.

Beatrix Willius

According to Apple the Rosetta bugs in AppleScript should be fixed in 11.4.

Something is seriously broken on your computer. While I hate BS like every other developer I don't have as many problems as you do.

Holy Moly!!!,

I have the random freeze, but I've had it for a couple of releases (3-4 back) and still on Catalina. I have no idea why, but its something with the OS or something I installed, because it still happens with my new iMac. If you ever figure it out let me know.

my two topics with
- very often the "remove attachment" command is greyed out, I never found a reason why for some emails it isn't available - this bug is at least since macOS 10.14
- has since macOS 10.15 a nice new feature - it learns and after a while it suggests a subfolder for moving a selected email. basically it works but it can't adapt to new situations. I have e.g. a subfolder 2020, where I moved all backup-status-emails in 2020. now for 2021 I created a 2021 subfolder and still after almost 5 month always suggest the 2020 folder, although I manually moved 5.000 emails to the 2021 folder manually

some of your detailed problems I have too, but after swiching from a intel macbook late 2013 with big sur to a macbook pro 13" m1 most problems I had vanished - I think because I made a clean setup, I only copied the documents from my timemachine-backup, I didn't used the migration assistant. I think that's the number one reason to have a solid macOS - don't use migration assistant and make a clean install with every second big macOS release

Most significant, for me, is that PDF Services no longer work. You could write a shell or python script to process a PDF, and access it from the print dialog's PDF button.
But now, the scripts are sandboxed so much that they can't read or write files, making them useless.

I've definitely had more multi-second freezes in recent releases; probably vastly more since Catalina.

This one:

> when I drag a window from a Retina display to a non-Retina one the font smoothing gets extra blurry.

I see this in High Sierra (which is still my main Mac) as well.

Related to displays, a bug that seemed to appear in Catalina (possibly Mojave), probably also only relevant for mixed Retina + non-Retina: when available displays change (e.g. you connect one), windows sometimes get moved to the very edge of a display such that they are hard to grab and move back to a proper location. More rarely (haven't seen this in months), they get moved to an outright impossible location: you can still see in Mission Control that they exist, but they are assigned to coordinates within a display that the display doesn't have.

(It's possible that this later bug is related to sheets, and that, because sheets have been changed significantly in Big Sur, it effectively no longer happens.)

I’m really skeptical of this “you just need a clean setup” advice because I see many of the same issues on Macs where I’ve made a clean install for testing purposes.

My god. Is this really where we've come to with the Mac after all these years? When are the powers that be at Apple going to face the fact that they've created a bugs-on-top-of-bugs-on-top-of-bugs situation, and it's time to put the breaks on the yearly OS upgrade train and instead put all their energy into fixing bugs!?!?

To me, the biggest, most appalling bugs revolve around Finder. How can it be that we all see such common, reproducible things like outdated folder contents and blatantly inaccurate disk/folder content stats? It's totally unacceptable, and is anyone at Apple working on fixing it? It certainly doesn't appear to be the case...

@ Ben:

>But now, the scripts are sandboxed so much that they can't read or write files, making them useless.


I looked into that and… can't figure out a way around it.

I wrapped a shell script in a bundle, code-signed it, had it assessed with Gatekeeper, gave it Full Disk Access (there doesn't seem to be a GUI way to give it just access to, say, my home dir), and and according to Console, TCC is even happy with the result — but regardless, if I then run this service from a Print dialog, writes seem to silently fail.

Plus one:

AirDrop window being unclickable from time to time, both device icons and the cancel button.

@Jonathan Safari beach balling has something to do with either Bookmarks or Cloudd. My guess is something to do with syncing Tabs and Bookmarks across devices. Super annoying.

@2cents Yes on WindowsServer usage.

And the most annoying problem, none of the recent release of macOS had any different to the way I work. i.e None of the new features make any difference. So apart from UI upgrade, the OS is essentially the same. But it has been getting more unstable with every release.

If most of these features aren't important. How about spend a release or two just doing bug fixing.

The one that drives me up the wall is Notification Centre hanging -- I don't get notifications, then I notice my fans are running high, so I click on the date and nothing happens, and I know I'm having this problem.

I open activity monitor and Notification Centre is hogging a CPU. I kill it, and everything goes back to normal. For a few hours, or days.

I'm told this only happens with external displays attached, but I haven't validated that.

Norbert Heger

Regarding Show in Finder just opening a home folder window: I was able to fix this by deleting Finder preferences (via `defaults delete`) and then relaunching Finder (via Control-Option-click on Finder’s Dock icon).

Marc Wilson

I'm going to ask the same question I ask of everyone... you're using Big Sur why?

Thing A doesn't do things the way you want them done, or has problems doing them at all. Thing B does what you want in the way you want it done. But you insist on using Thing A.


Hasn't everyone learned by now to wait until the last release of a particular version of $MACOS before considering installing it? Yes, if you bought an M1, you're kinda stuck, but sheesh! Catalina has security updates for another year yet.

@Marc It’s hard to be a Mac/iOS developer on Catalina because the current version of Xcode requires Big Sur.

Marc Wilson

I can sympathize, but then it really should be development over >>> there, and the real world over >>> here. Considering the pain points in your list, it's time to get another box, put macOS on it, and call it the dev machine.

@Marc That’s what I did during the Big Sur beta and the first few releases. But it’s also extra work to keep things separate, and some things that I want to test and debug need a real system, not a clean dev machine. So eventually it’s just easier to upgrade the main Mac, and that helps with discovering more Big Sur–specific bugs in my apps, too.

@ Marc: IME, Big Sur is overall _less_ buggy than Catalina (we can quibble over whether that's saying much).

If the goal were to go to a more reliable release, it would probably have to be something even older like Mojave. And at that point, other concerns come into play. A few months from now, for example, Apple will probably stop offering security updates for it.

@Sören I did stay on Mojave for over two years for that reason. But I’ll have to disagree that Big Sur being less buggy than Catalina (as evidenced by the above list).

Kevin Schumacher

Speaking as someone who is still running Mojave on their primary computer, a 2018 Mac mini--because of 32-bit Steam games that can't run on Catalina, and also the giant scary-sounding bugs that I've heard so much about with it--and High Sierra on their second primary computer (cross-border situation with my husband), a 2009 Mac Pro flashed to believe it's a 2010 with an upgraded CPU and an Nvidia GPU, which I can't upgrade past 10.13 because Apple and Nvidia can't get their damn crap together so Nvidia can release drivers for their GPUs in Mojave or later...

I'm in the market for a new computer to replace the 2009 Mac Pro. And right now, I'm basically only considering a 2018/early 2020 Mac mini (the early 2020 speedbumped Intel version apparently still reports as a 2018) either completely downgraded to Mojave, or maybe running Catalina with a Mojave partition for playing Steam games, and an eGPU enclosure with an AMD GPU. Although right now it is literally impossible to buy an AMD GPU that isn't $2,000 on eBay, so I don't know when I'll be able to upgrade. Big Sur isn't even a thought right now because of all the problems reported with it. I don't have the need to run Xcode. Though it would be nice to run a more recent version of NetNewsWire, most software I use is still at feature parity on Mojave versus current versions, so I'm OK with it for now.

(That said, this bridgeOS bug in Mojave, where it crashes during sleep, is absolutely maddening. Trying to predict how I will find it in the morning--whether the mini will be asleep like I left it, awake like it shouldn't be, or having crashed and no screen output but without turning off the system (and very warm like it's doing something, despite not responding and having to force it to power down)--is like Russian roulette.


I am stunned by your list of problems because . . . I have a few but nothing like your list. I have a 2017 27" iMac. It's been upgraded using Migration Assistant since at least Sierra. I haven't done serious development work on it since Mojave.

But still, it gets exercised . . . a lot—just an email and youtube viewer it ain't.

Are you *sure* it wouldn't be useful to build a seriously sterilized system from scratch?


The most frequent bugs I see are that Finder quits silently and I have to relaunch it, USB thumb drives disappear and I have to remove and reinsert them to use again, and spotlight results are awful now and default to items that I never use (“Bluetooth” will show “Bluetooth File Exchange”, which I have never ever used, instead of the Bluetooth system pref).

For what it's worth, none of my friends who have upgraded to Big Sur have reported any issues to me; nor have I had any trouble at all with Big Sur, which is running on two machines.

Old Unix Geek

@Dave Fultz,

Call me old fashioned, but upgrades should not break things. If they do, they are downgrades. Michael should not spend his life rebuilding Macs because Apple did its job badly. It had one job: make the OS better. It failed. That means it's not testing its code correctly, and that's pathetic. Add fewer features, get them right.

@Dave Fultz I’m seeing most of these issues on multiple Macs including ones with fresh installations.

Well, I have a "new" one. Ever since I upgraded to Big Sur 11.4, kernel_task is almost constantly active throttling down my CPU. I've cleaned up the vents, started monitoring the temperature, and even with the fans at full blast and the CPU temperature in the low 60s it keeps throttling down my machine to the point of unusability.

I suspect lack of testing in older hardware (and a lousy choice of thermal curves), since my machine never behaved consistently like this even though it was already a bit sensitive to heat.

Someone _really_ ought to re-tune these things.

Well, I've now been fighting kernel_task stalls for two weeks, and video playback seems to stop working after a few hours. Full saga:

Circling back after a couple of weeks with some interesting findings:

I think I've narrowed down the cause for my daily stalls - Big Sur 11.4 apparently did something to my Wi-Fi card (perhaps a firmware upgrade) that causes kernel_task to stall and take up insane amounts of CPU load when trying to use my 5GHz network (which, by the way, was working before the update). Took me two weeks to figure out because I was on a wired connection, but the link above has the full troubleshooting saga and I'm leaving here a copy of the log lines that pop up in Console, for Google juice:

ARPT: 2859.550473: wlc_phy_rx_iq_est_acphy: SPINWAIT ERROR : IQ measurement timed out
ARPT: 2859.550487: wl0: fatal error, reinitializing, total count of reinit's[65], @'wlapi_wlc_fatal_error':701

Even if the Wi-Fi card suddenly developed a fault (unlikely), this is a serious incapacitating bug.

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