Using an external hard drive is the recommended approach to using LR on multiple computers. Keep the images and the catalog on the external drive; move the drive to other computer as needed.
There is no need to copy the files to the internal drives of the computers; use the files on the external drive.
You do need to be making read-only backups of your catalog and images; you could use your desktop computer's drive for this purpose but you would never open these files in LR directly.
Your images are not "in" Lightroom; they are on the hard drive, just like all your documents and spreadsheets. The catalog (database) just references your images by path and file name on the hard drive.
LR is a single-computer system. If you are going to try to use multiple instances of a catalog on different computers, which is VERY MUCH not recommended, you need to choose one instance of the catalog as the master and then manually sync from and to it:
- Call the catalog on the external drive the master.
- Copy the master to the internal drive of the desktop.
- Open the local copy on the desktop.
- Do your edits.
- Close LR.
- Copy the local catalog back to the external drive to update the master catalog.
If you are going to do this, a shell script is the best way to do it while minimizing the user errors.
I suggest you always use the External drive for LR access to the catalog file and all your images. If you want a second copy of both your images and the catalog on the internal drive of the Mac desktop system as a backup then just Copy them from the external to the internal drive of the desktop using Finder, the Mac OS X File Manager program, but do not access the catalog file from that copy.
Thank you so much for your help, I really appreciate it.
If using multiple instances of a catalogue on different computers is not recommended, then what is the best/recommended way to do it? I'm not fussed as to how I "sync" the two computers, I just want to do it the way that is the best.
Thank you, I really appreciate your help.
I would not try Syncing the 2 computers. If you store the REAL Catalog file, IE the one you use to make all changes and imports to, on the external drive there is no reason to sync the 2 computers. You use the desktop system as a Backup of the images and catalog file.
You never Access that Backup from LR installed on the desktop. It is just a Backup!!!!!! .
All good advice here.
I would suggest that you do not use the Internal Hard Drive of the computer as a backup as it will very quickly become filled. Instead, get a second identical External Hard Drive and use an app such as SuperDuper - Shirt Pocket - to keep the 2 discs synchronized.
Alternatively, you can backup to the cloud with one of the backup services available. This avoids the confusion and problems of keeping computers synchronized.
Okay, that makes sense. Thank you so much for your help.
Thank you for your advice and help, I really appreciate it.