Given I was having issues with importing files into Aperture in the 10.13 PB, and Photos is one of the apps to see some improvements, I thought I'd take it for another spin. Most of my ~35k pictures are referenced outside Aperture, but even so the library size was 55GB after some cleansing. When it had finished importing into Photos it was slightly smaller at just under 50GB. I've been playing around with it for a couple of days, replicating some Smart Groups and checking star rating and keywords. Whilst it's still missing some of the stuff I regularly use in Aperture and I'll need to rethink my workflow for importing and backing up files, it might work. That said, in the few days I've been playing, I've left it running so it would scan for people/faces and in that time the library has grown to over 130GB, and it still has about 8000 pictures to scan. Why is this, and will it drop back down once this is complete. More than double the file size of Aperture is crazy, which was pretty big given most of my original images sit outside the library as reference files. I also did an import into Lightroom (the lack of iCloud is a problem) and that catalogue was less than 5GB! Any ideas?