How to sync LrC catalogs on two different devices?

The only way to see the files on both computers via Lightroom Classic is to put the catalog file and all photos on an external disk, and move the external disk from one computer to the other as needed.

Lightroom-Classic on two computer systems are separate entities. There is no connection or syncing between two Lr-Classic catalogs.

Two solutions are-

1)  On the MacBook use a 'Travel' catalog and when you return home use the function to [Import from another Catalog] to merge the MacBook Catalog (and photo files) with the iMac catalog.

Creating and Merging Catalogs in Lightroom Classic for a Location Shoot - YouTube

2) Consider using the cloud version of Lightroom on the MacBook. Photos imported to the MacBook will sync to the Cloud and automatically sync 'down' to the Lr-Classic catalog on the iMac. (A 20GB   cloud storage limit may need consideration if you are a prolific 'shooter'.)

in the future, to find the best place to post your message, use the list here, https://community.adobe.com/

p.s. i don't think the adobe website, and forums in particular, are easy to navigate, so don't spend a lot of time searching that forum list. do your best and we'll move the post (like this one has already been moved) if it helps you get responses.

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