2019 27 in 5k iMac Shuts down while using Lightroom (HELP)

[K & C Studios]

2019  27in 5k IMac

Version 10.15.7

3.6Ghz 8-core Intel Core I9

64GB 2667 MHZ DDR4

Radeon Pro Vega 48 8GBOk 

I have been having issue with 27 iMac shutting down while using Lightroom.
This happens during normal use. Applying presets adjusting white balance, brightness.
Nothing major . Times very, but it may be 20 min or 30 min before it shuts down. Sometimes less then a min.

I have been to apple store. On first visit it showed I had bad memory and it was replaced. Sadly issue still there. On second visit they ran complete diagnostic and everything came back normal no issues detected. At this stage I factory reset my Mac . I have purchased 64gb memory from crucial. I had the original Apple memory replaced. Unfortunately the issue is still there. Something is wrong but I cannot figure out what. I am turning to all of you for some guidance.

[dj_paige]

Computer crashing is always a bad driver, or a hardware malfunction. Re-install all drivers. Run diagnostics on ALL hardware, and make sure the cooling system is working properly (all fans running, no vents blocked, case vaccuumed out)

[charliemar57]

I am having the same issue my machine has simular specs but not as much ram. But mine shutdown is very sporadic. I do not think it is related to heat. I'm gussing the power supply is under rated for the i9s. I have not taken it to the apple store because I know from past experances it never happens in the store. The machine is under apple care so hopefully the powersupply will die and then I can get it fixed.

[dj_paige]

I do not think it is related to heat.

Why?

[charliemar57]

I run istat menus to monitor the cpu and other temps. The cpus were at 120F the GPU was about the same.

[K & C Studios]

Take it to the Apple store. My issues was related to power unit. Once they replaced it and it worked perfectly. 

[dj_paige]

What about the other advice I have given above? Have you tried that?

[charliemar57]

I did do a clean install when the problem first started. and then added back the  software/hardware alittle at a time. Because it happens so random it is hard to pinpoint. I am leaning leaning to a hardware problem. The computer checks out fine with the apple diagnostics. 

[DdeGannes]

@ Charlie, you have raised your issue in an old thread which was started in Nov 2020. At that time Mac users were experiencing multiple problems with Lightroom Classic most of those issues were resolved with the update to Lightroom Classic 10.2 which is the latest version available and the updating of macOS 11 Big Sur.

Please provide details of your present system specs! Do not say the latest or fully up to date provide the specific version numbers.

[charliemar57]

OS 11.31 lightroom11.3.1. I only have this problem of shutting down with 2 apps. Lightroom and Xplane 11 (flight sim) I know both apps can be resource intensive. I also have a few hard drives and SSD's attached. I have go thought them are replaced all the cases with powered cases so I not taking power from the imac. Any usb devices that will require power like my Wacom tablet is plugged into a thunderbolt dock. When using the computer for email, surfing or programing there is never an issue. I have an external drive with Mojave on it and I will have the same issues. So that's why i thinking hardware. I have applecare but until I can make it happen on command it's not worth arguing with Apple. I have found they are not helpful with sporadic problems.

 

[DdeGannes]

Ok so you have the latest version of LrC i.e 10.2 (ACR equivalent 13.2) and I have no knowledge of the other application you indicate is involved. I would suggest that you do not run them at the same time until you can solve your problem.

Just a thought out of the box, the name of the other app involved it may be a gaming app that is GPU intensive, Lightroom Classic is GPU intensive (needs 4GB) with certain edits in the Develop Module. There is an option in Lr preferences to turn off the GPU usage.

Good luck.