Some Users Experiencing System Crashes on macOS 10.15.4, Especially During Large File Transfers

A sizeable number of Mac users are experiencing occasional system crashes after updating to macOS Catalina version 10.15.4, released a few weeks ago.

macos catalina imac macbook pro
The crashing issue appears to be most prominent when users attempt to make large file transfers. In a forum post, SoftRAID described the issue as a bug and said that it is working with Apple engineers on a fix for macOS 10.15.5, or a workaround.

SoftRAID said the issue extends to Apple-formatted disks:

There is a serious issue with 10.15.4.

It shows up in different scenarios, even on Apple disks but is more likely when there are lots of IO threads. We think it is a threading issue. So while SoftRAID volumes are hit the hardest (its now hard to copy more than 30GB of data at a time), all systems are impacted by this.

In our bug report to Apple, we used a method to reproduce the problem with ONLY Apple formatted disks. Takes longer to reproduce, but that is more likely to get a faster fix to the user base.

Other users on macOS 10.15.4 have experienced crashes after waking their Mac from sleep, with affected systems suffering a kernel panic and rebooting to the Apple logo, according to comments shared on the Apple Support Communities, MacRumors Forums, Reddit, and Twitter.

After updating to macOS 10.15.4, users may also experience continuous spinning up and spinning down of connected hard drives when a Mac is supposed to be asleep, which could result in damage to the drive, according to Jeremy Horwitz.

We've reached out to Apple for comment and we will provide an update if we hear back.

Related Forum: macOS Catalina

Popular Stories

iOS 26 Feature

iOS 26.1 to iOS 26.4 Will Add These New Features to Your iPhone

Wednesday October 1, 2025 1:26 pm PDT by
iOS 26 was released last month, but the software train never stops, and iOS 26.1 beta testing is already underway. So far, iOS 26.1 makes both Apple Intelligence and Live Translation on compatible AirPods available in additional languages, and it includes some other minor changes across Apple Music, Calendar, Photos, and Safari. More features and changes will follow in future versions,...
iPhone 17 vs Air and Pros Feature

New iPhones See 'Stronger Than Expected' Demand With One Exception

Thursday October 2, 2025 7:26 am PDT by
Nearly two weeks after the iPhone 17 series launched, analysts at investment banking firm Morgan Stanley said demand for the devices has been "modestly stronger than we originally expected," based on a combination of extended shipping estimates on Apple's online store and information it gathered from Apple's supply chain. There has been strong early demand for the iPhone 17, iPhone 17 Pro,...
space black mbp

Here's Every New Apple Product That Leaked Yesterday

Wednesday October 1, 2025 8:27 am PDT by
A handful of upcoming Apple products leaked yesterday, through a combination of YouTube videos out of Russia and U.S. Federal Communications Commission (FCC) documents that were released, despite Apple's confidentiality requests. The leaked products include an iPad Pro with an M5 chip, as well as updated MacBook Pro and Apple Vision Pro models. All of these devices had already been rumored...
Apple 2025 Thumb 1

Apple's 2025 Product Roadmap: What's Still Coming

Wednesday October 1, 2025 3:56 pm PDT by
Apple's two big yearly events, WWDC and the iPhone launch, are done and over with, but there are still some new products that we're expecting to see before the end of the year. Apple TV The Apple TV hasn't been updated since 2022, so it's due for a refresh. It doesn't look like Apple is going to change the design of its set-top box, but we can expect a faster chip Apple code suggests...
macbook air prime day 2025

M5 MacBook Air: Release Date, Features, and Performance Predictions

Friday October 3, 2025 3:39 am PDT by
The MacBook Air is Apple's most popular laptop – a thin, fanless machine that wields quiet power thanks to the efficiency of Apple silicon. While the M4 model isn't exactly old, attention is already turning to its successor. Apple doesn't telegraph new product launches ahead of time, but we can draw a surprisingly clear picture of what to expect by looking at Apple's silicon roadmap,...
Tim Cook Rainbow

Apple Event in October? Here's What to Expect

Monday September 29, 2025 9:31 am PDT by
Apple's annual iPhone event is in the rearview mirror, but rumors suggest the company plans to release a handful of additional products before the year ends. Will there be another Apple event this October? We discuss the possibility below. Apple in October Apple's most recent October events were in 2021 and 2023. In 2022 and 2024, Apple did not host an October event. Instead, it...
apple wallet drivers license feature iPhone 15 pro teal 1

Apple's iPhone Driver's License Feature Now Available in 11 U.S. States

Tuesday September 30, 2025 6:40 am PDT by
In select U.S. states, residents can add their driver's license or state ID to the Wallet app on the iPhone and Apple Watch, providing a convenient and contactless way to display proof of identity or age at select airports and businesses, and in select apps. Apple recently revealed that the feature would soon be available in North Dakota, and starting today, the feature has officially gone...
iPhone 17e Feature 1

iPhone 17e: All the Rumors So Far

Thursday October 2, 2025 4:55 am PDT by
Earlier this year, Apple released the $599 iPhone 16e – a budget-friendly late addition to its iPhone 16 series and a replacement for its long-running entry-level iPhone SE line. Given the iPhone 17 lineup has now launched, can we expect an iPhone 17e anytime soon? If you're holding out for a more affordable device with the 17 moniker attached, here's everything we know so far about the...
iOS 26 Everything New Feature

26 Hidden iOS 26 Tricks to Change How You Use Your iPhone

Wednesday October 1, 2025 9:16 am PDT by
Apple released iOS 26 in mid-September, bringing a range of new features and changes to iPhones across the globe. But not all of the included improvements have been showcased with Apple's typical fanfare, and many are likely to have been overlooked. Below, we've highlighted 26 lesser known additions and enhancements that could potentially change how you use your iPhone on a daily basis. Got...

Top Rated Comments

MacFather Avatar
72 months ago
Deleted.
Score: 104 Votes (Like | Disagree)
cosmos Avatar
72 months ago
I was thinking of upgrading from Mojave until I was snapped back into reality by this article.
Score: 42 Votes (Like | Disagree)
MakeAppleAwesomeAgain Avatar
72 months ago
Yesterday I did something I haven't done in 15 years of using macOS, having used every major release and patch release. I've downgraded my MBA '13 to Mojave. It became unusable with Catalina. The process sucks, I'm still reinstalling and configuring stuff but I guess it's worth it. Since 10.15.4 it couldn't even wakeup without crashing, last week I got a full system freeze when I was just editing a document and this weekend I had a kernel panic. SSD is fine, I've ran memtest for hours, there nothing wrong with this Macbook. I've been running 10.15 since it came out and it's by far the worst macOS release ever. Lion and Yosemite were heaven compared to Catalina.
Score: 39 Votes (Like | Disagree)
BootsWalking Avatar
72 months ago
The "I'm a Mac" thing hasn't aged very well.
Score: 28 Votes (Like | Disagree)
jonnysods Avatar
72 months ago
Its this stuff that makes me wish they would go back to the 1.5+ year OS cycle. I know they are stuck because they like to do them all at once - but the pressure to put features into each build causes issues. Imagine 1.5-2 years of rock solid Mojave development and fixes, then come out with Catalina, and have time to perfect it.
Score: 26 Votes (Like | Disagree)
c.s. Avatar
72 months ago
Still on Mojave. Longest I've ever waited to upgrade the OS. Will probably just skip Catalina altogether.
Score: 26 Votes (Like | Disagree)