It’s a question that comes up over and over again, because people expect it to be complicated.  It’s not really!  Even moving Windows to Mac is a straightforward operation.

First, a bit of preparation will go a long towards preventing headaches…

1. Make sure your regular backups are up to date.
2. Set Lightroom’s folder panel to show just a few top level folders, to make it easy to relink them if they get confused in the move.  Instructions are here: http://www.lightroomqueen.com/blog/2008/12/17/i-have-a-long-list-of-folders-can-i-change-it-to-show-the-folder-hierarchy/
3. Install Lightroom (the program) on the new computer.  No need to install off the cd and then install updates, as each update is the entire program, so just skip along to the latest update which can be downloaded from Adobe’s website.

Now we’re ready to move.  Think about how you’re going to move the files – an external hard drive is the easiest option.

If you’re switching from Windows to Mac in the move, remember that OS X can’t natively write to a NTFS formatted drive, so either format as FAT32, or remember you’ll need to copy the data off and reformat again once you’ve finished moving.

You’ll want to transfer all of your presets, which are entirely cross-platform, over to the new computer, and possibly your preferences file too, if you’re moving Windows to Windows or Mac to Mac.  Don’t forget any plug-ins, and custom DNG profiles that you’ve created too.  You’ll find all of the file locations here: http://www.lightroomqueen.com/blog/2008/12/15/default-file-locations-lightroom-2/ Bear in mind that these are hidden locations on Windows, so you’ll need to turn go to Start menu > Control Panel > Folder Options > View > Advanced Settings and turn on ‘Show hidden files and folders’ in order to find them.

You have 2 options for the catalog and images move – either moving and relinking, which is generally my preferred option, or using Export as Catalog, which is handy if data is scattered across your computer.

Option 1 – move and relink

1. Find and copy your catalog to the new computer.  If you don’t know where to find it, go to Edit menu > Catalog Settings (Windows) or Lightroom menu > Catalog Settings (Mac) and it’ll be listed there.
2. Find and copy your images to the new computer.  Personally I like to use File Synchronization software to make sure I don’t miss anything.
3. Open your catalog on the new computer – double clicking on it is the quickest way.
4. There may now be question marks all over the place, if it can’t find the files.  It’s just a question of relinking those top level folders with the updated folder locations.  Instructions here: http://www.lightroomqueen.com/blog/2009/02/21/lightroom-thinks-my-photos-are-missing-how-do-i-%ef%ac%81x-it/
5. Double check everything is up and running before you delete the old computer!

Option 2 – export as catalog

1. Open Lightroom and go to File > Export as Catalog.
2. Select a location on your external hard drive, and ‘include preview files’ and ‘include negative files’ so that everything is taken along.
3. Press Export and let it run.  It will take some time.
4. Now on your external hard drive should be a catalog, with an Images folder containing all of your negative files.  It should warn you if it couldn’t transfer some files.
5. Transfer the external hard drive to the other machine.
6. You could transfer the catalog itself (the *.lrcat file and *.lrdata file) to the new machine’s internal hard drive if you wish.
7. Double-click on the catalog to open it.
8. If you move the images, the drive letter changes between machines, or you’re moving between operating systems (i.e. Windows to Mac) you may still have to do the relinking listed in option 1.
9. Double check everything is up and running before you delete the old computer!

You’re all set!

Excerpt from Adobe Lightroom 2 – The Missing FAQ

Missing files are usually a result of files being moved or renamed outside of Lightroom, perhaps in Explorer or Finder.  In this case, Lightroom loses tracks of the files.

They can be identified by a little question mark in the corner of the grid thumbnail.
If the entire folder can no longer be found, the folder name in the Folders panel will go grey with a question mark folder icon.  They used to go red in LR1.

When you go in to the Develop module, Lightroom will tell you that the file is offline or missing.

If the whole folder is missing and the folder name has turned grey, you can right-click on the folder and select ‘Find Missing Folder…’.  Point Lightroom to the right folder, and it should update the links for all of the files contained in that folder.  That’s the quickest option!

If the folder is still showing as recognised, you’ll need to relocate individual images, but Lightroom will try to help where it can.

To locate a missing file, click on the question mark icon, and the following dialog will appear.

Click Locate to find the missing file.

Locate the missing file and press Select.  Check the ‘Find nearby missing photos’ checkbox shown in the dialog above in order to re-link other files in the same folder.
If you have renamed the files outside of Lightroom, each file will need linking individually.
If Lightroom appears slow to re-link related photos, restart Lightroom to force a search for file locations.
A few preventative measures, to avoid missing files in future:

1. Rename any files before importing into Lightroom, or use Lightroom to rename them.
2. Set Lightroom’s folder list to show the full folder hierarchy to a single root level folder.  If all of the files are moved from their expected locations, they can easily be updated using the ‘Find Missing Folder…’ command in the top level folder right-click menu, or by using the ‘Update Folder Location…’ command even if they’re not yet marked as missing.
3. Move any files or folders within Lightroom’s own interface, simply by dragging and dropping around the folders panel.  Folders can only be moved one at a time.

Since the Photoshop User magazine came out, I’ve had a number of emails asking about my own workflow for DNG files and backups, so let me run through it quickly.  There is no right or wrong workflow – this is just what works well for me.

I want the best of both worlds – I want smaller file sizes, no sidecars and updated previews on my working drive so I use DNG for my main working files, but maybe one day I might want a proprietary raw file for something, so I keep one of my offline backups as a proprietary raw format.  I want the files to have matching names and folder structure, so converting on import doesn’t work for me, so this is my current workflow:

1. Import with backup turned on – this is a temporary backup, just in case something goes wrong before I finish sorting.
2. Rename files – the proprietary raw files now have the new names
3. Use the OS or File Sync software to copy the images to my offline backup structure.  Export as Original format to the other drive would do the same.  That drive is then disconnected again.
4. Select all in Grid view and go to Library menu > Convert Photo to DNG with ‘delete originals after successful comversion’ turned on swaps my proprietary raw files in the catalog for new DNG files, and removes the proprietary files from the hard drive.
5. That leaves me with DNG files in the catalog, complete with all of the settings that were previously attached to the proprietary raw files.  The proprietary files are safely backed up on my offline drive, with matching file names and a matching folder structure, just in case I ever need one.  Ok, I’ll admit, I’ve never been back to them yet, but you never know! 

NO!  Lightroom’s backup just backs up the catalog, and it doesn’t contain your photos – only references to where to find them and the data about them.  You need to back your photos up separately.

Every time I hear someone say ‘I deleted the photos because I thought Lightroom backed them up’, my heart sinks.

I can’t say this loudly enough – back up your photos as well as letting Lightroom back up its catalog.  Lightroom doesn’t do that for you.

Thanks to Dan Tull, Adobe Engineer, for making an excellent point… you’re not keeping your backups with the original catalog, right?

Ok, by default, the catalogs are backed up in a ‘backups’ subfolder alongside the original catalog.    If you don’t regularly back up that whole drive to a second drive, what will happen when your main drive dies?  You’ll have dutifully run Lightroom’s backups – and they’ll be on that dead drive along with the original catalog.  That’s not much help!

So what are you going to do?  You really need to have a backup system that very regularly backs up your entire hard drive contents to another hard drive (not just another partition) AND you still need to run Lightroom’s backups.  Lightroom’s backups are a safety net against catalog corruption, and the hard drive backup protects against hard drive failure.  You definitely want both.

If you haven’t got that set up, at least in the meantime set Lightroom’s backup to back up the catalog to another drive, otherwise all your hard work could be gone with that nasty click click click of a dying drive.

So how do you change the backup location?  Here’s the instructions from Adobe Lightroom 2 – The Missing FAQ:

How do I change the backup location?

The backup directory is changed in the Back Up Catalog dialog, which appears when a backup is due to run.

If you need to show the Back Up Catalog dialog to change the location when a backup is not normally due, you can run a backup on demand.  To do so, go to Catalog Settings > General panel and change the backup frequency temporarily to ‘when Lightroom starts’.  Restart Lightroom so that the backup dialog comes up, and then you’ll be able to change the backup location.

Don’t forget to then change it back to your normal backup schedule.

All you NAPP members out there, check the Lightroom section of your latest Photoshop User magazine (March 2009) for MY article on DNG!

For those of you who aren’t NAPP members, you’ll want to sign up now!!!

In the meantime, here’s the main bullets points directly from Adobe Lightroom 2 – The Missing FAQ

File size
DNG files are generally 10-40% smaller than their original proprietary format, depending partly on the size of the preview that you choose to embed.

XMP Sidecars
Proprietary raw formats have their XMP data stored as a sidecar XMP file, whereas DNG files have that information embedded within the single DNG file.  The question is, do you find sidecar files a pro or con?

Long Term Storage
The DNG format is openly documented, which means that it should be supported indefinitely, whereas proprietary formats such as CR2, NEF, RAF etc. are not openly documented.  Will you be able to find a raw converter in 20 years time that will convert a proprietary format when that camera model is ancient history?

Manufacturer’s Software
Most manufacturer’s own software will not read a DNG file, only their own proprietary formats.  Do you ever need to open a file in the manufacturer’s own software?  If so, you’d want to embed the proprietary raw file – it can be extracted use the DNG Converter tool, however it does negate the file size benefits.

MakerNotes
While there is DNG support for MakerNotes, some manufacturers don’t stick to the rules, and therefore MakerNotes embedded in an undocumented format can’t always be carried over to the DNG file, however if you’re not sure what the MakerNotes are, you probably won’t miss them.

Check the Photoshop User article for lots more pros, cons and how to’s.