Adobe has tested running the latest versions of Lightroom Classic and Lightroom 6.x with macOS v10.13 (High Sierra) and found the issue documented in this article below.

Adobe recommends that customers update Lightroom to the current version prior to updating to macOS v10.13 (High Sierra). Adobe also recommends that customers do their own testing on a nonproduction partition to ensure that the new macOS works with their current hardware and drivers.

If you do encounter issues that are not already documented, feel free to report them on our feedback site.

Issue

Lightroom Classic CC 7.0 or Lightroom CC 2015.12/Lightroom 6.12 crashes when you have multiple external devices such as memory card readers or hard-drives connected to your Mac. 

Solution

This issue has been fixed in Lightroom Classic CC 7.0.1 and Lightroom 6.13/CC 2015.13 releases. 

Use the Creative Cloud desktop app to update Lightroom to the latest version. For details, see Update Creative Cloud apps.