Very soon I will be getting a new computer.
I currently have my Lightroom library on an external HDD
That is currenlty connected to my macbook pro via usb.
Previously, the Lightroom library ext HDD was connected to my iMac.
When moved from the iMac to the MBP - i lost all the ratings and color labels.
When i move to this new machine, i want to be able to keep the ratings and colors.
I don't want to physically copy the image files to the new machine - i want to keep using the ext HDD.
If the catalog is on the hard drive with the images, and pointing at the images, there's no reason anything should get lost. If you've custom labels, this is stored as part of preferences, which are machine specific. If you use Migration assistant, this should bring these over though.
Currently the ext HDD only has the images
The catalog is on the MBP - should/can i move that to the ext HDD?
Also, do you mean the migration assistant within macOS?
I wasn't planning on using that - was going to try to start this new machine from scratch
You can literally copy the entire Lightroom Catalog folder over to the hard drive (with Lightroom Classic closed). Double click on the catalog on the drive, once copied, to open it. It should see the images immediately as they're still in the expected location.
The catalog folder will contain files like Lightroom.lrcat, Lightroom Previews.lrdata, Lightroom.lrcat-data. Make sure it's all copied. The previews files can get pretty big.
Thanks. Do I need to delete the catalog file on the mbp once I copy it over? Or is ok to have two copies of the file ( on on mbp, one on the ext HDD)
Personally, I do not suggest having copies on different location of the same catalog.
The "day of confusion" will come ....
I agree. I wouldn't delete the original one until I knew the copy is working though. As to backups, you change backup frequency to 'When Lightroom Next Exits' when the copy catalog is running. This will create a zipped backup of the current catalog.
I second that. This is what I suggest in all classes. Set the backup to "Everytime LrC exits". This way the option to save your work is automatically shown after the work done. The dialog has the option to still quit without backup if you did not do any work and were just "looking" 😉
I forgot .... You definitely should/must have backups of the catalog though