You need to set the option in the Lightroom Catalog Settings to create backups. YOu can pick every tiime you exit Lightroom. or once a day, or once a week, whatever is appropriate for you. Then when you exit Lightroom, you will be asked if you want to make a backup, and you will have the option to select a disk and folder to place the backup of the catalog file. The disk chosen MUST (that's MUST) be a different disk than the disk your working catalog file is on.
You must (that's MUST) also make backups of the photos, because Lightroom does not do this for you. You should use third-party utilities that will do this for you automatically (because all of us humans forget at times). The backups of your photos should preserve your folder structure and file names, and MUST (that's MUST) go on a different disk than your original photos.
What I get from your answer is: I could have my working catalog file on
my iMac flash drive (which will be backed up by Time Machine) and it should
also get backed up on an external disk dedicated to the working catalog
file backup. Then I need a second external disk to back up my photos, and
of course an external disk to hold my original photos.
No, that doesn't sound like what I said.
First, I don't know what you mean by "flash drive", but what I understand the term "flash drive" to mean is not in any way a suitable location for your catalog file. Your catalog file needs to be on a regular hard drive (internal or external) or SSD drive.
You can certainly put the backup of the catalog file and the backup on the photos on the same external drive, I never said you need two external drives.
The newer iMacs can be outfitted with solid state flash drive, if one
chooses to do so, instead of the usual hard drive. That's what I opted
for, a 512 gigabyte flash drive. It was recommended to me as more reliable
than a hard drive with it's mechanical moving arm and rotating disk.
Why are you thinking a flash drive to be unsuitable for a catalog file?
Glad to hear the catalog backup and photos backup can be on the same drive.
Obivously you mean something different than my understanding of the term "flash drive". That's fine, go ahead and use it.
I'm puzzled by the paradigm shift from pre-LRX to LR6 - because contrary to your answer here it 'appears' that a standard preference setting has changed or disappeared in LR6
I say 'appears' because despite the plethora of advice online and your answer here it makes absolutely no sense to me that Lightroom does not also make a backup of the source DNG file
In previous versions of Lightroom I have backup folders of source DNG files on my external drives and made no alterations to default preferences in LR - in addition to the LR Catalogue stored on a local drive
However in LR6 this behaviour does not continue - I have searched in Preferences and hidden away there is a tick box setting 'Make Second Copy' - though that is incorrect if there is no 'first copy'
Can you explain in a straightforward way (i.e. not with a 30 minute video) how to set Preferences in LR6 to emulate the behaviour of previous versions - so that when Importing the DNG source file is saved to a chosen external destination?
Thanks for your help
MacBook Pro 10.10.5
External storage hard drive
Importing Leica DNG from SD card
ian_creative you need to update to LR 6.3, where the behavior of the import dialog box is the same as in previous major versions of Lightroom. (Lightroom 6.2 and 6.2.1 had a "new" import dialog box that people hated, so the old import dialog box is back in LR 6.3)