How to prevent macOS Catalina 10.15.4 from hanging when copying large files

AppleInsider

Apple's macOS Catalina 10.15.4 is proving problematic for users with very large video or image files. Until Apple fixes it, here's the workaround.

OWC ThunderBay 8 RAID system

A bug specific to macOS Catalina 10.15.4 has been causing problems for filmmakers and photographers with large numbers of files, and very large projects to copy. It's affecting users transferring data from camera cards to RAID arrays on their Macs, and the symptom is that the Finder on those Macs simply freeze.

You can still move your mouse, so the Mac hardware is responsive to some extent. But, the copy does not complete, and won't ever complete.

OWC discovered the bug in macOS after investigating complaints from users of its RAID systems.

"We alerted Apple engineers to the issue," says OWC's Tim Standing. "I can't say when Apple will release the fix for this problem, but in the past, when they have been alerted to a hang or kernel panic, they had it resolved in the next update to macOS."

The simplest solution is to stay on macOS Catalina 10.15.3 or update to macOS 10.15.5, but the problematic new version came out on March 24 so it has been some time since release at this point. There was a supplementary update on April 8, to fix a FaceTime bug, and it's not clear whether this hanging problem was introduced then. So if you are on 10.15.3, or you have 10.15.4 and haven't yet installed the April 8 update, wait until the next release.

If you're having the problem, this is the solution. Note that it involves changing NVRAM settings -- and this requires you to disable the Mac's System Integrity Protection (SIP). Doing this means your machine is more vulnerable to malware.

How to change NVRAM settings

First, disable SIP.

• Restart and then hold down Command-R until the Apple logo appears


• When the Mac has booted into Recovery mode, launch Terminal from the Utilities menu


• In Terminal, type csrutil disable


• Restart

You must be in Recovery mode before you use these Terminal commands

Next, change the NVRAM settings themselves. With your Mac booted and running, launch Terminal.

• In Terminal, type sudo nvram boot-args="dart=0"


• Restart your Mac again

That will have done it, but you need to check. When the Mac has fully booted up, launch Terminal again.

• In terminal, type nvram boot-args


• Terminal should respond with boot-args dart=0

If you see any other response, you need to go back to the beginning and work through this again.

After Apple fixes the problem

Presumably Apple will fix this issue in the next update to macOS Catalina 10.15.4, but whether it does or not, you're going to have to undo this work in order to find out. This time, you need to do the steps in reverse order, so that you alter the NVRAM settings, then you reenable the SIP.

• Launch Terminal and type sudo nvram boot-args=


• Restart your Mac


• Confirm the changes by typing nvram boot-args in Terminal

If it's worked, you'll see Terminal respond with boot-args. Now reenable the System Integrity Protection.

• Restart and then hold down Command-R until the Apple logo appears


• When the Mac has booted into Recovery mode, launch Terminal from the Utilities menu


• In Terminal, type csrutil enable

You should see Terminal respond with the message Successfully enabled System Integrity Protection. Please restart.... Restart your Mac as normal and everything will be back to normal.

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sflocal

I experienced this precise problem the moment I upgraded to the .4 release and tried copying a 1.5TB file from my Promise R8 to a Promise R6 RAID drive.  It was brutal and created a huge amount of headaches for me.

I'm not sure what's been going on with Apple's MacOS updates lately.  Have they had an exodus of the good MacOS software engineers or are they using low-grade rookies working on crucial OS codes?  

kestral

I prevent Catalina from hanging when copying large files by using Mojave instead.

emoeller

Catalina has been a hot mess for me.  I now have it on only one laptop (a loaded 2018 MBP 15:"), and I rarely use it.   I get the most work done on a much older 15" MBP running High Sierra.  Takes seconds (not minutes) to boot up, almost never hangs or has any kind of operational issue, and of course I can still use my 32b apps.  

lkrupp

sflocal said:

I experienced this precise problem the moment I upgraded to the .4 release and tried copying a 1.5TB file from my Promise R8 to a Promise R6 RAID drive.  It was brutal and created a huge amount of headaches for me.

I'm not sure what's been going on with Apple's MacOS updates lately.  Have they had an exodus of the good MacOS software engineers or are they using low-grade rookies working on crucial OS codes?  

People have been saying things like that since the dawn of Apple time. Get a clue and peruse the Apple Discussion forums, tech blogs, and right here on AI. Every release of of every update is solemnly declared to be the absolute worst pos Apple has ever foisted upon the public. The post below yours sarcastically says to avoid this issue by using Mojave. Well, guess what, people are still ragging on Mojave as being a stinking pile of shit. Nothing unusual has been going on with updates lately. Bugs come and go. One is fixed and another one pops up because of the fix. Happens all the time. Finally, someone please present us with an example the perfect operating system that has no discernible issues or bugs. You can’t because nothing like that exists, or has existed... ever.

And guess what? If you use your setup as your primary source of income then it’s on you to make sure an update doesn’t screw your workflow. So you applied the update without any testing of your RAID? You just assumed all would be well. I’m sorry but it’s hard to feel empathy for that.

I'll bet the first thing you do when 10.15.5 comes out is test it first.

cpsro

Is this only happening with RAID volumes (whether Apple RAID or SoftRAID)? I haven't encountered it [knock on wood] with any internal SSD. (Externally I've been using ZFS but that RAID enclosure is currently mounted on a Linux system and hasn't been used under 10.15.4 yet. btw: I'm greatly enjoying the use of ZFS for cross-platform RAID. It was much easier to get up and running than I was expecting.)

sflocal

lkrupp said:

sflocal said:

I experienced this precise problem the moment I upgraded to the .4 release and tried copying a 1.5TB file from my Promise R8 to a Promise R6 RAID drive.  It was brutal and created a huge amount of headaches for me.

I'm not sure what's been going on with Apple's MacOS updates lately.  Have they had an exodus of the good MacOS software engineers or are they using low-grade rookies working on crucial OS codes?  

People have been saying things like that since the dawn of Apple time. Get a clue and peruse the Apple Discussion forums, tech blogs, and right here on AI. Every release of of every update is solemnly declared to be the absolute worst pos Apple has ever foisted upon the public. The post below yours sarcastically says to avoid this issue by using Mojave. Well, guess what, people are still ragging on Mojave as being a stinking pile of shit. Nothing unusual has been going on with updates lately. Bugs come and go. One is fixed and another one pops up because of the fix. Happens all the time. Finally, someone please present us with an example the perfect operating system that has no discernible issues or bugs. You can’t because nothing like that exists, or has existed... ever.

And guess what? If you use your setup as your primary source of income then it’s on you to make sure an update doesn’t screw your workflow. So you applied the update without any testing of your RAID? You just assumed all would be well. I’m sorry but it’s hard to feel empathy for that.

I'll bet the first thing you do when 10.15.5 comes out is test it first.

Wow Einstein.  I'm impressed.  You got it all figured out.  Amazing that Apple hasn't reached out to you to lead their engineering team! *rolls eyes*

However, since you seem to know more about my setup than I do, the part of my mind you failed to read was that I did test the update.  I have two other MacOS workstations that had zero problems and felt quite comfortable installing it on the final system.  I have two RAID towers with the 2nd one as a mirror-backup of the first.  So... yes, I could have hosed my entire system and not cared.  But you knew that right?

Heck, I could have wiped out my workstation completely and reinstall from scratch with zero concern.  My headache was trying to determine why that update messed up that one particular Mac and not the other two.  And yes, I will be installing .5 when it comes out because part of my JOB is to test the updates before rolling them out to other users.  

Getting a little cranky being sheltered for all this time?

Mike Wuerthele

cpsro said:

Is this only happening with RAID volumes (whether Apple RAID or SoftRAID)? I haven't encountered it [knock on wood] with any internal SSD. (Externally I've been using ZFS but that RAID enclosure is currently mounted on a Linux system and hasn't been used under 10.15.4 yet. btw: I'm greatly enjoying the use of ZFS for cross-platform RAID. It was much easier to get up and running than I was expecting.)

No. Single volumes too.

It isn't universal, but isn't uncommon.

cpsro

This workaround doesn't just leave your system more vulnerable to malware while SIP is disabled. Setting dart=0 disables Intel's VT-d and the protections it provides.

lkrupp

sflocal said:

lkrupp said:

sflocal said:

I experienced this precise problem the moment I upgraded to the .4 release and tried copying a 1.5TB file from my Promise R8 to a Promise R6 RAID drive.  It was brutal and created a huge amount of headaches for me.

I'm not sure what's been going on with Apple's MacOS updates lately.  Have they had an exodus of the good MacOS software engineers or are they using low-grade rookies working on crucial OS codes?  

People have been saying things like that since the dawn of Apple time. Get a clue and peruse the Apple Discussion forums, tech blogs, and right here on AI. Every release of of every update is solemnly declared to be the absolute worst pos Apple has ever foisted upon the public. The post below yours sarcastically says to avoid this issue by using Mojave. Well, guess what, people are still ragging on Mojave as being a stinking pile of shit. Nothing unusual has been going on with updates lately. Bugs come and go. One is fixed and another one pops up because of the fix. Happens all the time. Finally, someone please present us with an example the perfect operating system that has no discernible issues or bugs. You can’t because nothing like that exists, or has existed... ever.

And guess what? If you use your setup as your primary source of income then it’s on you to make sure an update doesn’t screw your workflow. So you applied the update without any testing of your RAID? You just assumed all would be well. I’m sorry but it’s hard to feel empathy for that.

I'll bet the first thing you do when 10.15.5 comes out is test it first.

Wow Einstein.  I'm impressed.  You got it all figured out.  Amazing that Apple hasn't reached out to you to lead their engineering team! *rolls eyes*

However, since you seem to know more about my setup than I do, the part of my mind you failed to read was that I did test the update.  I have two other MacOS workstations that had zero problems and felt quite comfortable installing it on the final system.  I have two RAID towers with the 2nd one as a mirror-backup of the first.  So... yes, I could have hosed my entire system and not cared.  But you knew that right?

Heck, I could have wiped out my workstation completely and reinstall from scratch with zero concern.  My headache was trying to determine why that update messed up that one particular Mac and not the other two.  And yes, I will be installing .5 when it comes out because part of my JOB is to test the updates before rolling them out to other users.  

Getting a little cranky being sheltered for all this time?

No. Snark and condescension is why I’m a little cranky. Encounter a problem? Label Apple’s engineers as incompetent, lazy, know-nothing rookies. 

jtd

lkrupp said:

sflocal said:

I experienced this precise problem the moment I upgraded to the .4 release and tried copying a 1.5TB file from my Promise R8 to a Promise R6 RAID drive.  It was brutal and created a huge amount of headaches for me.

I'm not sure what's been going on with Apple's MacOS updates lately.  Have they had an exodus of the good MacOS software engineers or are they using low-grade rookies working on crucial OS codes?  

People have been saying things like that since the dawn of Apple time. Get a clue and peruse the Apple Discussion forums, tech blogs, and right here on AI. Every release of of every update is solemnly declared to be the absolute worst pos Apple has ever foisted upon the public. The post below yours sarcastically says to avoid this issue by using Mojave. Well, guess what, people are still ragging on Mojave as being a stinking pile of shit. Nothing unusual has been going on with updates lately. Bugs come and go. One is fixed and another one pops up because of the fix. Happens all the time. Finally, someone please present us with an example the perfect operating system that has no discernible issues or bugs. You can’t because nothing like that exists, or has existed... ever.

And guess what? If you use your setup as your primary source of income then it’s on you to make sure an update doesn’t screw your workflow. So you applied the update without any testing of your RAID? You just assumed all would be well. I’m sorry but it’s hard to feel empathy for that.

I'll bet the first thing you do when 10.15.5 comes out is test it first.

This just isn't accurate. Read why Apple's most recent OS releases ARE so buggy compared to previous releases from an actual Apple engineer. It's getting worse.

https://tidbits.com/2019/10/21/six-reasons-why-ios-13-and-catalina-are-so-buggy/ ;

Wgkrueger

I’m guessing that if the terminal cp command we’re used the hangs wouldn’t happen. 

macminion

I smell a macOS Pro version.  Remove the fluff apps.  Too many pros risking their livelihood on fluff apps not needed in macOS.  Beef up the OS - not the fluff.

dieter

I was struggling with this issue for over a week driving me nuts (finder & terminal's rsync display this problem in my new MacPro). Thanks for mentioning the underlying cause, I thought hardware was faulty... Let's hope a 'real' fix comes soon.

Marvin

macminion said:

I smell a macOS Pro version.  Remove the fluff apps.  Too many pros risking their livelihood on fluff apps not needed in macOS.  Beef up the OS - not the fluff.

Just a roll-back system would be enough, it's not easy to test all kinds of 3rd party hardware. The Mac system in Catalina is on a separate read-only partition. This could allow not only multiple Mac systems to be easily installed but also the updates. I think system updates should be overrides of the core system and to roll-back to the core would just need removing the update.

There's an update on the following article suggesting disabling the RAID write cache works for some people:

https://blog.macsales.com/60773-why-is-my-mac-hanging-when-copying-files-after-upgrading-to-macos-catalina-10-15-4/

According to the site below, setting dart=0 "turns off the system PCI address mapper (DART) on 64-bit hardware. DART is required on machines with more than 2GB of physical memory but is enabled by default on all machines, regardless of their memory sizes."

https://osxeon.wordpress.com/2015/08/10/boot-argument-options-in-os-x/

Some people commented that this setting disables their wifi.

polymnia

Funny, I JUST upgraded to Catalina a couple weeks ago, seemed to have finally shaken its bugs and Adobe seemed to be running well according to the internet. 

I haven’t encountered this exact problem yet, and I’ve spend the last week consolidating my client work that has been accumulating for years from a Synology diskstation & multiple external drives attached to my Catalina production Mac to a Promise RAID. I have had some copy jobs crash the finder, but nothing I haven’t seen before and they were easy enough to restart after rebooting the system. 

The reason for consolidating is I kind of hate being in charge of my own storage pool with associated backup hardware. I signed up for the Dropbox unlimited advanced plan: unlimited storage. I’ll keep one copy of my work on the RAID, backup to Backblaze, and sync whatever needed to my laptop & mobile devices. The grand total work is something like 20TB and growing fast. It was time to either outsource the task or invest in two shiny new, high capacity RAID systems (working & backup). I’m happy to (mostly) retire from the file storage game. 

jdb8167

I’ve been getting kernel panics overnight from I suspect my OWC SoftRAID setup. It’s hard to tell since they happen when unattended. Since they are panics and they being reported I hope Apple will fix them on the next update or forward them to OWC’s SoftRAID team depending on who is responsible. Probably not related but they seem to be similar enough that I wonder if the issue is always a hang or is it sometimes a panic like I’m seeing. 

dysamoria

lkrupp said:

sflocal said:

I experienced this precise problem the moment I upgraded to the .4 release and tried copying a 1.5TB file from my Promise R8 to a Promise R6 RAID drive.  It was brutal and created a huge amount of headaches for me.

I'm not sure what's been going on with Apple's MacOS updates lately.  Have they had an exodus of the good MacOS software engineers or are they using low-grade rookies working on crucial OS codes?  

People have been saying things like that since the dawn of Apple time. Get a clue and peruse the Apple Discussion forums, tech blogs, and right here on AI. Every release of of every update is solemnly declared to be the absolute worst pos Apple has ever foisted upon the public. The post below yours sarcastically says to avoid this issue by using Mojave. Well, guess what, people are still ragging on Mojave as being a stinking pile of shit. Nothing unusual has been going on with updates lately. Bugs come and go. One is fixed and another one pops up because of the fix. Happens all the time. Finally, someone please present us with an example the perfect operating system that has no discernible issues or bugs. You can’t because nothing like that exists, or has existed... ever.

And guess what? If you use your setup as your primary source of income then it’s on you to make sure an update doesn’t screw your workflow. So you applied the update without any testing of your RAID? You just assumed all would be well. I’m sorry but it’s hard to feel empathy for that.

I'll bet the first thing you do when 10.15.5 comes out is test it first.

Dude, it’s like he insulted your mother or kicked your dog. Chill out. 

dysamoria

lkrupp said:

sflocal said:

lkrupp said:

sflocal said:

I experienced this precise problem the moment I upgraded to the .4 release and tried copying a 1.5TB file from my Promise R8 to a Promise R6 RAID drive.  It was brutal and created a huge amount of headaches for me.

I'm not sure what's been going on with Apple's MacOS updates lately.  Have they had an exodus of the good MacOS software engineers or are they using low-grade rookies working on crucial OS codes?  

People have been saying things like that since the dawn of Apple time. Get a clue and peruse the Apple Discussion forums, tech blogs, and right here on AI. Every release of of every update is solemnly declared to be the absolute worst pos Apple has ever foisted upon the public. The post below yours sarcastically says to avoid this issue by using Mojave. Well, guess what, people are still ragging on Mojave as being a stinking pile of shit. Nothing unusual has been going on with updates lately. Bugs come and go. One is fixed and another one pops up because of the fix. Happens all the time. Finally, someone please present us with an example the perfect operating system that has no discernible issues or bugs. You can’t because nothing like that exists, or has existed... ever.

And guess what? If you use your setup as your primary source of income then it’s on you to make sure an update doesn’t screw your workflow. So you applied the update without any testing of your RAID? You just assumed all would be well. I’m sorry but it’s hard to feel empathy for that.

I'll bet the first thing you do when 10.15.5 comes out is test it first.

Wow Einstein.  I'm impressed.  You got it all figured out.  Amazing that Apple hasn't reached out to you to lead their engineering team! *rolls eyes*

However, since you seem to know more about my setup than I do, the part of my mind you failed to read was that I did test the update.  I have two other MacOS workstations that had zero problems and felt quite comfortable installing it on the final system.  I have two RAID towers with the 2nd one as a mirror-backup of the first.  So... yes, I could have hosed my entire system and not cared.  But you knew that right?

Heck, I could have wiped out my workstation completely and reinstall from scratch with zero concern.  My headache was trying to determine why that update messed up that one particular Mac and not the other two.  And yes, I will be installing .5 when it comes out because part of my JOB is to test the updates before rolling them out to other users.  

Getting a little cranky being sheltered for all this time?

No. Snark and condescension is why I’m a little cranky. Encounter a problem? Label Apple’s engineers as incompetent, lazy, know-nothing rookies. 

Are you one of Apple’s engineers? Stop being defensive and acting offended for Apple. Apple are capable of mounting their own defense, and they do deserve criticism for the slipping quality control. It’s pretty clear that Apple have been having problems with regressions and new bugs in new releases. They still haven’t fixed long-standing bugs introduced in iOS 7! It even got into the media that Apple themselves recognized a need to restructure their internal habits and code change policies.

dysamoria

Apple need to do more testing of Mac OS in professional environments before releasing updates. I assume they’re not eating their own dog food on their internal server end, just like they’re not eating it in their data centers (it’s all generic Linux server contracts). Maybe if they used their own products on their own internal critical services (and developed their own internal tools), they’d see why it’s important to have better quality control on their own products...

dieter

I confirm, disabling SIP & changing NVRAM settings disabled my WiFi... ethernet works fine.