How to disable parallel photo exporting?

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​@Purple_ MacOS 15.7.3

So disabling that option does improve the situation a lot, but unfortunately not enough

It’s possible you’re tripping over a memory leak in the graphics driver that gets much worse when the image renderings in export run in parallel. Unfortunately, the only way to update a graphics driver on Mac is to update to a new version of Mac OS.  If you’re reluctant to update to Mac OS 26 yet, and you have a spare external disk sitting around, you could try dual-booting with 15.7.3 and 26:

https://support.apple.com/en-us/118282

That is not normal so there is probably a bug somewhere, but it’s hard to say whether it’s in Lightroom Classic, macOS, or both. I can only offer two observations: 

I’ve frequently done bulk exports with Lightroom Classic on Apple Silicon Macs with 32-36GB of Unified Memory and never seen any serious memory pressure problems. During bulk export I have seen memory usage spike higher than in the past, but not into red memory pressure. I think more memory usage is expected in the versions after GPU acceleration was added to exporting, because using GPU acceleration would naturally require more graphics memory. With that in mind, one troubleshooting experiment is to temporarily disable GPU acceleration for exports even though that would mean reverting to longer bulk export times. You can disable the option Preferences/Performance/Use GPU For Export. If you try that, is bulk export memory usage markedly lower? If so, that could indicate that the problem might be related to graphics memory usage specifically.

Now, I’m not saying the memory problem never happens. Over the years there have been a number of posts here reporting that Lightroom Classic is using an absurdly high amount of memory, sometimes so high that macOS complains and asks you to close applications. But it is not common, it doesn't seem to happen to most users. However, I have sometimes seen similar excessive memory use in Premiere, so I know problems like that do happen. But in both applications it seems to happen much less often than in the past, so maybe Adobe and Apple have been gradually addressing the edge cases.

As for “wearing down the SSD,” that’s probably unlikely because bulk exporting is something that happens for a short time occasionally (not constantly writing all day long). Also, after 10 years of Macs using non-removable SSDs, there still has not been any major trend of Macs becoming unusable because the SSD ran out of writes. The non-removable SSD still tends to last more years than most users care to keep using the same Mac. 

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Here’s a workaround that could reduce the number of concurrent exports by perhaps half:

1. Install the Run Any Command plugin.  It’s got 6-week free-trial period.

2. In the Export settings window’s Post-Process Actions panel, select Run Any Command and click Insert. Then in Command Per Image, type “date”:

3. When you export, a performance bug introduced by Adobe some years ago will prevent the Command Per Image from being run in parallel with that of other images being exported. On my Macbook, that results in about half the concurrency of exports.  

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a memory usage of up to 60GB

Something obviously seems to be misbehaving with your LR. In Activity Monitor, which particular memory column for the Lightroom Classic row are you looking at?

When I do a large batch export of hundreds of raws in my LR 15.2.1 / Mac OS 26.2 / Macbook Pro M2 Max 64 GB, I see Lightroom Classic Real Mem go up to 12 GB  and Memory (total physical memory used by LR) at 22 GB.