Imac 2019 27 Inch - Boot from SSD Crashing

[Mark8par]

Hi, I have a Imac Retina 27Inch 2019 and the internal drive has been failing. After doing a bit of investigation I decided to add an external NVMe (Crucial P510) with a Acasis 40Gbps enclosure and connected to the thunderbolt port. I followed the procedure to install the os on the external drive and to boot from it but the problem I am having is it randomly crashes/restarts and I cannot for the life of me think why.

I am running MacOS Sequoia

If anyone can help or give some guidance it would be appreciated.

Cheers

 

[Bigwaff]

Download and install EtreCheck. Run a report. Post results here. Will help folks understand your system, the error/crash, and offer advice.

EtreCheck

etrecheck.com

 

[gilby101]

What were the symptoms which led you to thinking that the internal drive was failing? Maybe it was something else which is still giving you trouble.

 

[Mark8par]

What were the symptoms which led you to thinking that the internal drive was failing? Maybe it was something else which is still giving you trouble.

the drive is not showing all of the time when I have attached the external ssd with os.

 

[Mark8par]

Performance: Excellent





Problem: Computer is restarting


Description:


Random restarts





Major Issues:


Anything that appears on this list needs immediate attention.





Failing hard drive - This computer has a hard drive that appears to be failing.


Kernel panics - This system has experienced kernel panics. This could be a sign of hardware failure.





Minor Issues:


These issues do not need immediate attention but they may indicate future problems or opportunities for improvement.





Apps with heavy CPU usage - There have been numerous cases of apps with heavy CPU usage.





Hardware Information:


Status: Supported


iMac Model: iMac19,1


3.7 GHz 6-Core Intel Core i5 (i5-9600K) CPU: 6-core


8 GB RAM - Upgradeable


BANK 0/ChannelA-DIMM0 - 4 GB DDR4 2667


BANK 1/ChannelA-DIMM1 - Empty


BANK 2/ChannelB-DIMM0 - 4 GB DDR4 2667


BANK 3/ChannelB-DIMM1 - Empty





Video Information:


Radeon Pro 580X - VRAM: 8 GB


iMac (built-in) 5120 x 2880





Drives:


disk0 - CT1000P510SSD8 1.00 TB (Solid State - TRIM: Yes)


External 8.0 GT/s x4 NVM Express


disk0s1 - EFI (MS-DOS FAT32) [EFI] 210 MB


disk0s2 [APFS Container] 1000.00 GB


disk1 [APFS Virtual drive] 1000.00 GB (Shared by 6 volumes)


disk1s1 - A********* - Data (APFS) [APFS Virtual drive] (243.75 GB used)


disk1s2 - Preboot (APFS) [APFS Preboot] (2.72 GB used)


disk1s3 - Recovery (APFS) [Recovery] (1.33 GB used)


disk1s4 (APFS) [APFS Container] (11.26 GB used)


disk1s4s1 - E****************D (APFS) [APFS Snapshot] (11.26 GB used)


disk1s5 - Update (APFS) (1 MB used)


disk1s6 - VM (APFS) [APFS VM] (1 MB used)





Mounted Volumes:


disk1s1 - A********* - Data [APFS Virtual drive]


Filesystem: APFS


Mount point: /System/Volumes/Data


Used: 243.75 GB


Shared values


Size: 1000.00 GB


Free: 740.72 GB


Available: 787.05 GB





disk1s2 - Preboot [APFS Preboot]


Filesystem: APFS


Mount point: /System/Volumes/Preboot


Used: 2.72 GB


Shared values


Size: 1000.00 GB


Free: 740.72 GB





disk1s4s1 - E****************D [APFS Snapshot]


Filesystem: APFS


Mount point: /


Read-only: Yes


Used: 11.26 GB


Shared values


Size: 1000.00 GB


Free: 740.72 GB


Available: 787.05 GB





disk1s5 - Update


Filesystem: APFS


Mount point: /System/Volumes/Update


Used: 1 MB


Shared values


Size: 1000.00 GB


Free: 740.72 GB





disk1s6 - VM [APFS VM]


Filesystem: APFS


Mount point: /System/Volumes/VM


Used: 1 MB


Shared values


Size: 1000.00 GB


Free: 740.72 GB





disk3s1 - Creedence11M6270.SECUREPKITRUSTSTOREASSETS_SECUREPKITRUSTSTORE_Cryptex


Filesystem: APFS


Disk Image


Mount point: /System/Library/AssetsV2/com_apple_MobileAsset_PKITrustStore/purpose_auto/6dd55b0d06633a00de6f57ccb910a66a5ba2409a.asset/.AssetData


Read-only: Yes


Size: 4 MB





USB:


USB 3.1 bus


Apple Inc. - FaceTime HD Camera (Built-in)


Apple Inc. - Magic Keyboard with Numeric Keypad





USB 3.1 bus


<Empty>





USB 3.1 bus


<Empty>





Network:


Interface en0: Ethernet


Interface bridge0: Thunderbolt Bridge


Interface en1: Wi-Fi


802.11 a/b/g/n/ac





iCloud information is limited without Full Disk Access





System Software:


macOS Sequoia 15.7.9 (24G830)


Installed 2026-08-18


Time since boot: About an hour





Security:


Gatekeeper: App Store and identified developers


System Integrity Protection: Enabled



Antivirus software: Apple





System Launch Daemons:


[Not Loaded] 43 Apple tasks


[Loaded] 194 Apple tasks


[Running] 177 Apple tasks


[Other] 4 Apple tasks





System Launch Agents:


[Not Loaded] 24 Apple tasks


[Loaded] 211 Apple tasks


[Running] 214 Apple tasks





User Login Items:


[Not Loaded] PasswordsMenuBarExtra (Apple - installed 2026-08-01)


Modern Login Item


/System/Applications/Passwords.app/Contents/Library/LoginItems/PasswordsMenuBarExtra.app





[Not Loaded] WeatherMenu (Apple - installed 2026-08-01)


Modern Login Item


/System/Applications/Weather.app/Contents/Library/LoginItems/WeatherMenu.app





[Not Loaded] DriveDxLoginItemHelper (Kirill Luzanov - installed 2026-09-01)


Modern Login Item


~/Downloads/DriveDx.app/Contents/Library/LoginItems/DriveDxLoginItemHelper.app





Applications:


402 Apple apps


7 3rd party apps


None


No unsigned apps





App Extensions:





Spotlight importers:


[Loaded] EtreCheckPro - ~/Downloads/EtreCheckPro.app





Backup:


Time Machine information is limited without Full Disk Access


Destinations:


i***************e [Local] (Last used)


6 local snapshots


Oldest local snapshot: 2026-08-29 22:49:30


Last local snapshot: 2026-09-03 11:07:17





Performance:


System Load: 1.50 (1 min ago) 1.40 (5 min ago) 0.98 (15 min ago)


Nominal I/O usage: 0.17 MB/s


File system: 16.18 seconds


Write speed: 2557 MB/s


Read speed: 2848 MB/s





CPU Usage Snapshot:


Type Overall


System: 1 %


User: 6 %


Idle: 93 %





Top Processes Snapshot by CPU:


Process (count) CPU (Source - Location)


EtreCheckPro 35.50 % (Etresoft, Inc.)


mdbulkimport 6.74 % (Apple)


WindowServer 5.22 % (Apple)


kernel_task 0.83 % (Apple)


bluetoothd 0.58 % (Apple)





Top Processes Snapshot by Memory:


Process (count) RAM usage (Source - Location)


EtreCheckPro 785 MB (Etresoft, Inc.)


Safari 155 MB (Apple)


com.apple.WebKit.WebContent (2) 148 MB (Apple)


AppleSpell 144 MB (Apple)


MTLCompilerService (12) 107 MB (Apple)





Top Processes Snapshot by Network Use:


Process Input / Output (Source - Location)


com.apple.WebKit.Networking 14 MB / 59 KB (Apple)


apsd 135 KB / 1 MB (Apple)


mDNSResponder 653 KB / 392 KB (Apple)


netbiosd 40 KB / 17 KB (Apple)


rapportd 41 KB / 10 KB (Apple)





Top Processes Snapshot by Energy Use:


Process (count) Energy (0-100) (Source - Location)


WindowServer 4 (Apple)


sysmond 0 (Apple)


bluetoothd 0 (Apple)


Activity Monitor 0 (Apple)


UniversalControl 0 (Apple)





Virtual Memory Information:


Physical RAM: 8 GB





Free RAM: 71 MB


Used RAM: 4.81 GB


Cached files: 3.12 GB





Available RAM: 3.19 GB


Swap Used: 0 B





Software Installs (past 60 days):


Install Date Name (Version)


2026-08-18 macOS 15.7.9 (15.7.9) - Software update


2026-08-18 XProtectPlistConfigData (5355) - Software update


2026-08-18 MRTConfigData (1.93) - Software update


2026-08-18 Gatekeeper Compatibility Data (1.0) - Software update


2026-08-18 XProtectPayloads (157) - Software update


2026-08-18 Safari (26.6) - Software update


2026-08-19 XProtectCloudKitUpdate (5356) - XProtectUpdateService


2026-08-20 XProtectPlistConfigData (5356) - Software update


2026-08-26 XProtectCloudKitUpdate (5357) - XProtectUpdateService


2026-08-27 XProtectPlistConfigData (5357) - Software update


2026-08-27 Safari (26.6.1) - Software update


2026-09-01 Disk Speed Test (3.4.3) - App Store


2026-09-02 XProtectCloudKitUpdate (5358) - XProtectUpdateService


2026-09-02 XProtectPlistConfigData (5358) - Software update





Diagnostics Information (past 60 days):


2026-09-03 11:25:58 photoanalysisd - High CPU Use (3 times)


First occurrence: 2026-08-27 15:04:29


Executable: /System/Library/PrivateFrameworks/PhotoAnalysis.framework/Versions/A/Support/photoanalysisd





2026-09-03 10:33:34 spotlightknowledged - High CPU Use (11 times)


First occurrence: 2026-08-27 12:55:38


Executable: /System/Library/Frameworks/CoreSpotlight.framework/spotlightknowledged





2026-09-03 10:18:56 Notes.app - High CPU Use (5 times)


First occurrence: 2026-09-03 10:11:30


Executable: /System/Applications/Notes.app





2026-09-03 09:45:23 Kernel Panic (13 times)


First occurrence: 2026-08-27 17:58:43


Details:


panic(cpu 0 caller 0xffffff8014bf5c9a): nvme: ". Command timeout. Read


. fBuiltIn=1 MODEL=APPLE SSD SM1024L FW=CXS7LA0Q CSTS=0x1 US[1]=0x0 US


[0]=0x48f VID=0x144d DID=0xa804 CRITICAL_WARNING=0x0.\


Panicked task 0xffffff8b76a3b980: 237 threads: pid 0: kernel_task








2026-09-03 07:26:14 knowledgeconstructiond - High CPU Use (7 times)


First occurrence: 2026-08-27 15:13:39


Executable: /System/Library/PrivateFrameworks/IntelligencePlatformCore.framework/Versions/A/knowledgeconstructiond





2026-09-02 21:47:06 photolibraryd - High CPU Use (2 times)


First occurrence: 2026-08-29 18:28:35


Executable: /System/Library/PrivateFrameworks/PhotoLibraryServices.framework/Versions/A/Support/photolibraryd





2026-09-02 10:54:30 fileproviderd - High CPU Use (4 times)


First occurrence: 2026-08-27 19:55:23


Executable: /System/Library/Frameworks/FileProvider.framework/Support/fileproviderd





2026-09-02 10:53:40 Kernel Panic (4 times)


First occurrence: 2026-09-01 18:30:41


Details:


panic(cpu 1 caller 0xffffff800bcb480a): watchdog timeout: no checkins


from watchdogd in 90 seconds (30 total checkins since monitoring last


enabled)


Panicked task 0xffffff9df8805980: 144 threads: pid 0: kernel_task


3rd party NVMe controller. Command timeout. Read. fBuiltIn=0 MODEL=CT1


000P510SSD8 FW=K1CR5101 CSTS=0x1 US[1]=0x0 US[0]=0x52 VID=0xc0a9 DID=0


x560a CRITICAL_WARNING=0x0








2026-09-01 18:45:29 Kernel Panic


Details:


panic(cpu 3 caller 0xffffff80090f2293): watchdogd[1016] exited -- exi


t reason namespace 2 subcode 0xa description: none


3rd party NVMe controller. Command timeout. Read. fBuiltIn=0 MODEL=CT1


000P510SSD8 FW=K1CR5101 CSTS=0x1 US[1]=0x0 US[0]=0x52 VID=0xc0a9 DID=0


x560a CRITICAL_WARNING=0x0








2026-09-01 18:11:23 Kernel Panic


Details:


panic(cpu 0 caller 0xffffff800a3f5c9a): nvme: ". Command timeout. Read


. fBuiltIn=1 MODEL=APPLE SSD SM1024L FW=CXS7LA0Q CSTS=0x1 US[1]=0x0 US


[0]=0x5b5 VID=0x144d DID=0xa804 CRITICAL_WARNING=0x0.\


Panicked task 0xffffff902813f980: 236 threads: pid 0: kernel_task


3rd party NVMe controller. Command timeout. Read. fBuiltIn=0 MODEL=CT1


000P510SSD8 FW=K1CR5101 CSTS=0x1 US[1]=0x0 US[0]=0x52 VID=0xc0a9 DID=0


x560a CRITICAL_WARNING=0x0








2026-08-28 16:24:11 backupd - High CPU Use (3 times)


First occurrence: 2026-08-27 17:37:24


Executable: /System/Library/CoreServices/TimeMachine/backupd





2026-08-28 15:59:19 Sharing - Crash (2 times)


First occurrence: 2026-08-28 15:21:07


Executable: /System/Library/ExtensionKit/Extensions/Sharing.appex/Contents/MacOS/Sharing





2026-08-28 15:53:42 cloudphotod - High CPU Use


Executable: /System/Library/PrivateFrameworks/CloudPhotoLibrary.framework/Versions/A/Support/cloudphotod





2026-08-28 14:37:15 suggestd - High CPU Use


Executable: /System/Library/PrivateFrameworks/CoreSuggestions.framework/Versions/A/Support/suggestd





2026-08-28 02:49:39 Kernel Panic


Details:


panic(cpu 3 caller 0xffffff801a8f2293): initproc exited -- exit reaso


n namespace 2 subcode 0xa description: none


3rd party NVMe controller. PCI link down. Delete IO submission queue.


fBuiltIn=0 MODEL=CT1000P510SSD8 FW=K1CR5101 CSTS=0xffffffff US[1]=0x0


US[0]=0x44 VID=0xffff DID=0xffff CRITICAL_WARNING=0x0











End of report

 

[Fishrrman]

Try a different enclosure.

This could make a world of difference.

 

[Bigwaff]

Yes. A different enclosure, preferably one that is not bus powered. Make sure you have Energy settings such that storage devices never sleep. If issue persists, you may have to opt for powered hub or dock. You have several storage related kernel panics occurring. Consistent power and a different enclosure may eliminate kernel panics coming from the external device going offline, especially if the enclosure is getting really hot during use. The other storage related kernel panic is from the internal SSD failing. You may have to remove or replace that component to eliminate the kernel panics. If you do, opt to replace. Booting from internal storage is preferable to external.. and much more performant.

 

[DeltaMac]

The internal drive (a blade SSD), assuming it is failing, may still be affecting the operation of your iMac. I have seen failing internal drives that are still connected, continue to affect the operation of the computer, even if you are not actually trying use that internal drive for anything. You may need to "open it up", and physically remove that blade SSD. That may be your best way forward. You could even consider moving your external blade SSD from the external enclosure to the internal blade slot. You would need to add the correct adapter to that blade, Sintech makes a good adapter that you can use.