Migrating from Windows to Mac Losing Metadata

…My photos all gor moved to a Pictures directory…Opening my catalog on the mac, pictures show up with an "!". I guess I can override from the catalog but I have over 13000 pictures. Is there a better way to move the photos over? Or a way to do a mass change from the catalog?

By @Benjamin304194009ael

The first thing to do is the last thing you said: A mass change from the catalog.

The only reason photos show a [!] is that the catalog was remembering the locations of originals using their Windows folder paths, and now those don’t work of course. Now the root path is
[name of Mac internal SSD]/Users/[your account name]/Pictures/

Hopefully it copied the pictures while preserving the exact folder hierarchy you were using in Windows, because then you can quickly fix this in Lightroom Classic. Open the catalog, and in the Library module, Folders panel, right-click a top level folder and choose Update Folder Location. Select where that folder is on your Mac now (in the Pictures folder), and click Choose. Lightroom Classic will then update not only the parent folder you selected, but also all subfolders and pictures/videos inside that top level folder.

If right-click isn’t configured for the trackpad/mouse/stylus you’re using on your Mac, open that context menu by Control-clicking instead.

This is the same step you’d take if you were running out of space on internal storage and wanted to move the pictures to an external volume. You’d move them, and then use Update Folder Location to tell Lightroom Classic where the top level folder went.

Fixing the creation/modification dates might take a little more work. I’m surprised that they migrated that way, but I’ll bet it didn’t alter the Capture Date (which is different). I suppose you could try copying over the files manually from the PC to the Mac and see if the file creation/modification dates are better preserved that way, but test on a small batch first.

It's usually recommended not to use the migration assistant on a Mac even from Mac to Mac and always to start fresh as there have been known to be strange results at times with Adobe applications and migrations. But with that said, while the creation date and last modified dates in the Mac OS Finder will show the date of the transfer, the creation date in the Mac OS Finder should not overwrite the metadata of the picture. There is a good article about migrating lightroom catalogs here that may help and can guide you through the exclamation mark on your catalog: https://www.lightroomqueen.com/how-move-lightroom-to-new-computer/