I find that 9 times out of 10, weird crashes in OSX are the result of permission privileges not allowing the app to write cache files where it needs to.
Some of those problems I have had with w/2.91, but I just appended the objects in a new file of 2.8+.
I should say that these problems seemed to occur after “upgrading?” to Big Sur. By the way, DON’T upgrade for a few releases of this OS, it’s terribly buggy and frustrating.
Before 2.8, I thought that Blender quality might go to hell and it has, as more attention is diverted new features for professionals. Even the big studios insisted on LTS because the bug lists were perpetually too long. I’ve almost given up on Blender a few times.
Thanks a lot for testing this.
Would be great if you could try to render the file on 2.82.
For me it worked perfectly well, while it constantly crashed on newer versions.
2.82 is still super stable for me. And my projects are often very big and very chaotic.
But newer Mac versions are really unusable for me as well, unfortunately.
I don’t think that’s the case here. 2.82 renders the file without problems. While newer versions constantly crash. (On my Macs.)
Unless newer versions of Blender deal with permission privileges differently than 2.82.
@JollyJumper I just want to say it again. I was having the same issues with 2.83 and 2.90 where a crash would corrupt a single collection.
Since using 2.91 this issue has disappeared. I also upgraded to Big Sur at the the same time I started using 2.91, so I’m not sure if it was an Catalina issue or 2.83.
Not sure if you’re gun shy of 2.91, but it has been stable for me.
This is working with a 42GB file with over 90 collections.
Tim
I’m really glad to hear this Timothy.
As you noticed I am very sceptical, since I had so much trouble.
And with 2.91 alpha I still had issues. (The file I could not render for example I did on 2.91 alpha.)
If these issues are really resolved, it would be amazing! 
Maybe Big Sur did help.
Which brings me to the question of upgrading to Bug Sur or not.
Ingapambi recommends not to upgrade yet, just a few posts ago. 
But if it allows me to use recent Blender versions, it’s surely worth trying.
(Plus I will have to upgrade anyway as soon as Big Sur supports the Navi2 AMD cards.)
Totally understandable. I didn’t have the option of staying with 2.81 since I desperately need the new Motion Blur settings for EEVEE. So ours and others corruption issues made me switch fully to Bootcamp after losing 10hrs of animation work, with no hope of getting it back. Before that I was just using the Bootcamp version for rendering, since EEVEE tends to render considerably faster there.
I just want to say that my issues where only the “corruption” issues and not with rendering, so unless those are resolved you may still need to stay put.
I know you’re a seasoned Mac user but just want to add tips for others who may be reading this.
Guidelines for maybe why Big Sur and 2.91 is working smooth for me:
- I always “clean” install a new OS i.e. Catalina to Big Sur (usually not including “point versions”). This means I don’t install from backup. I save my documents folder to an external SSD along with any pertinent file locations i.e. Daz Studio save location, etc.
Once the new OS is installed, I then reinstall needed programs from their proper websites or App store. I don’t install programs from a back up.
I then install each App’s prior saved files, from the external SSD, back into their respective locations. Usually this is just copying the documents folder over, minus the few programs like Daz that has it’s own special file location.
-
When installing a new “point” version of Blender I once again install from a clean version. I don’t transfer settings from previous versions and I don’t bulk copy the add-on’s folder to the new version. I’ll once again reinstall all previous Add-ons from their respective market place locations and then reinstall.
-
For files that I’m still in the middle of working on when making the switch to the new Blender version, I’ll open a new Blender file and append each collection.
This doesn’t necessarily clear me of any funky legacy setting that maybe is causing an issue, but it’s the closet thing I can think of when installing a new Blender version.
Hope this helps,
Tim
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Ha, ha, ha. That was very elegantly put. 
Yes, I am ‘very seasoned’… played with the very first Macintosh, when my dad bought it in 84. And from then on I followed every generation of Macs. But I am also an extremely lazy and technically uninterested user. So thanks for your tips.
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Yeah thats the reason why I keep my old macPros running with new GPUS. They work fantastic with windows10.
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Hey, just joining the community here! Unfortunately, partly, because I’m definitely experiencing these problems as well. Trying to use 2.91, I’m more or less a beginner but have managed to getting to do a couple of commercial projects in Blender - which is proving to be somewhat stressful because of the constant fear of corrupted files. I’ve lost at least two personal projects to this, with no (working) backups - they both can be appended and the corruption is down to a single object, but in one case it’s a bit too much work to put the scene back together and in another the object in question is basically the main part of the whole thing. So - they’re gone, more or less.
I’m not sure if I have anything new to add here, except in both cases the object in question was untouched for a (relatively) long time and then suddenly a common operation - just selecting some vertices (of an unrelated object), or switching to a different workspace or rendering mode (or something else, I can’t pin it down) would irreversibly crash and corrupt the whole thing, including the autosaved backup file.
Another perhaps unrelated thing is I’ve recently started getting crashes from rendering, either on the first frame or after a bunch (rendering overnight hardly ever works anymore) - also I’m not sure if the bug where the Mac would go to sleep and waking up would always crash Blender was ever fixed.
So - plently of issues, but super excited to learn Blender and be a part of this community. Using a MBP 16", 2019 (2,3Ghz i9) with 32Gb of RAM, if that’s of any help.
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Hi Petteri & welcome to BA!
Every little information helps. And every user writing about this issue helps to show the devs, that there are really quite a bunch of us Mac users out there, who would be super thankful if they would address and fix it. (I don’t want to complain, but I’m sure if this would have happened on Windows it would have been fixed instantly.)
CookItOff writes, that 2.91 on BigSur does not have these issues any more. I could not verify this, since I did not upgrade to BigSur yet.
On Catalina I still have issues with 2.91. So I would strongly recommend to use 2.82 for now. It’s the last stable version of Blender for Macs. Only with a stable version you can really enjoy Blender, I think. No worries about corrupt files at all. And basically no crashes at all, as well. The few missing features should not be a deal breaker. (Unless you need motion blur for Eevee.)
You can download older version of Blender from the Blender website. I think I posted a link somewhere in this thread.
The random nature of the corruption is the big problem here. I could also not figure out when and why it happened. The new undo system was a suspect. But it was not yet confirmed, as far as I know.
So, but now I wish you lot’s of fun with Blender!
I just want to say that “I personally” haven’t had the issue pop up after going to Big Sur and 2.91. This is to say that it may very well still exist and I’m just not triggering the bug like I was before.
I only say it’s gone on my part because I haven’t seen it since I upgraded, and I was getting it very frequently before. 
I know this issue is extremely frustrating cause we can’t nail it down to exactly what’s causing it. As of now we only know that it’s limited to a certain object, which will change from time to time, and limited to that object’s collection.
But beyond that it’s just so random.
Tim
Another data point for you: I’ve been using 2.83.3 LTS on macOS Sierra since that blender version was released. I’ve delivered a handful of 3D rendered scenes to use in videos, including some particle snowflakes this week. Delivered a finished piece today that I worked on for maybe 20 hours over the past week and a half, mostly tweaking particle settings and physics. I relied on blender’s add-on for exporting JSX to After Effects, using the resulting animation in After Effects to make a greeting card fly, spraying those particle snowflakes.
Simple stuff but quick to make on this Mac Pro with 32GB RAM. I wish the graphics cards were used by blender; they are AMDs. Anyway, blender’s been fairly stable, occasionally crashing when I try something intense like overdoing a subdivision setting. But blender’s been delivering results without me having to think about it much. In this case, about 1200 to 1400 frames of 1920x1080, 1500 snowflake particles. I use blender for fairly simple stuff, mostly elements for motion graphics for explainer videos or promotional spots.
Hi, I’m using the last stable version of blender and Mac Os big Sur and my life has become a nightmare. Between the files who take forever to open (280Mo on disk) and the ones who don’t open, the ones who crash, and blender who keeps crashing…
I’ve updated to big sur 2 months ago.
So now my only idea so far is to jump back to older version of blender and catalina. Loosing hours of work cannot be an option.
I’m very sorry to hear, Alexandre.
The only thing I can recommend is to use 2.82. It’s the last stable version for Mac and the only ‘solution’ that worked for me. Any newer version was a driving me mad.
(Would be interesting to hear if 2.82 works perfectly on Big Sur. So far I did not upgrade.)
Oh, and welcome to BA!!
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Just joined to throw my hat in the ring here too.
I’m a gamedev with some past experience in 3D art w/ Maya, and I’m brushing up on my skills/learning blender this week. I only have about 4 days of experience now, but in those 4 days I’m getting relatively frequent crashes, and almost all of them are happening after coming back to an open project after some time away. Like if I get up from my computer to eat lunch, when I come back my first command will crash Blender. It’s gotten to the point where I’m wary to actually start using this for real 3D work, as I’ve lost a good amount of work in test projects and tutorials.
OS: macOS Big Sur 11.1
Blender: 2.83.5 and now 2.91.0
Hardware: 2020 iMac, 3.8GHz 8-core i7, Radeon Pro 5500XT, 72GB RAM
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So I can confirm : many students with macOS cannot use this version.
It crashes, corrupts files, looses data in files
something serioulsy is wrong
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next student has the issue with files corrupted
THIS IS MESSED UP AND SERIOUSLY NEEDS TO BE RESOLVED !
does anybody know to what degree the devs are on this?
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I don’t really know what the devs are doing about it.
There used to be a few threads on the dev page.
Some of them got closed (eg: https://developer.blender.org/T80272) and continued in this one:
It would be really great to hear, what and if the devs are working on it. I think we are all aware, that the issue is difficult to track down, as it seems to appear randomly. But for Mac users this really is a serious problem which is worth some serious dev time.
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