Aperture-to-lightroom import hanging

Hi,

I'm trying to import a large Aperture library into Lightroom Classic (latest versions of both programs as of this morning), and unfortunately it keeps hanging. I'm wondering if anyone else has seen this before and has any advice on what changes/cleanup I can make to my Aperture library to solve this.

The Library has ~80k pictures, all referenced, of many different file types. I am importing copying to a new location, and I am using the option to import previews as well (so as not to lose all of the edits I have made in Aperture).

After running overnight, the process hung. Lightroom was still responsive, but the % complete stopped at 4%, the number of photos in the library (visible beneath the application modal status window) stopped at 4502, and Lightroom stopped using CPU. Nothing unusual appeared in the LibraryImporter.log file. I let it sit in this state for 12 hours with no change. I then hit Lightroom's cancel button and was able to browse the 4502 pictures that had been imported. (However, Lightroom was unwilling to close because it said an operation was still underway -- import in current location.)

Has anyone else encountered this? Any ideas?

Thanks!