# Question about backup lrprev files



## Drolleddu (Nov 1, 2012)

Hi to everyone! 
I'm just setting up my backup configuration of my photos, in order to have a couple of safe copies always available in case of crashes .
I'm using LR4 to edit my works, having dedicated catalogues for each shooting session rolleyes: yes.... I know that is not the best way to work with LR....but it work fine for my purposes....:nod. This happens in the main HDD in my pc.
Then everything is backed up first in an external HDD via SW (FreeFileSync) at the end of each editing session, and this first external HDD is then mirrored to a second one.
In this way I suppose to always have two safe copies in case of crashes of the working HDD .
What I backup every time is the complete "Photos" folder, that contains sub-folders with the RAW files and the LR catalogues (and everything inside them...).
Then my question: I've noticed, looking at what happens during the backup, that in this way also the lrprev folders and files has been backed up every time, and because the rule of the backup is that if a file isn't in the source folder but is in the target one it keeps the second one doing anything, the backup folder is growing up every time that I perform my backup... .
I think that I can exclude the lrprev folders and files from my backup, because they are created by LR only to speed up the visualization of the RAW file when showed in LR itself, right? I mean, I've an active catalogue with everything (included lrprev, of course) that is the one where I work files. The backup copies are only to be safe and don't loose anything, but in this copies is not mandatory to have also the lrprev, because in case of use of this catalogues, the lrprev will be created again by LR when opening the catalogue and the file (ok, slowly, but it doesn't matter ...). And I can also save space on HDDs...
I'm right with this approach? (ok, this is the real question )... Do you have any other suggestions or tricks? In which way you back up you work?

Bye
Pierluigi


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## Hal P Anderson (Nov 1, 2012)

Welcome to the forum!

You're right. You don't need to back up the previews. In the very rare instance that you need to go to your backups, LR will have to spend some time re-creating the previews, and that is a small price to pay.

Hal


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## Brad Snyder (Nov 1, 2012)

Elaborating on Hal's correct answer. It's not required to backup up the Preview folder/package, it will auto-regenerate upon need. Recognize that Previews are used only in the Library module. They have no use or accelerating function in the Develop module.

That said, it comes down to the individual economics/efficiency of your workflow. Many/most folks choose not to spend the hours and hard-drive space backing up the previews. Some practicing pros believe that they can't afford the down-time and lost efficiency that would come from having to regenerate the previews, and consequently choose to back them up anyway. (I'm not sure I buy that argument, but I'm willing to accept their perceived need.)


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## Drolleddu (Nov 1, 2012)

Hal P Anderson said:


> Welcome to the forum!
> 
> You're right. You don't need to back up the previews. In the very rare instance that you need to go to your backups, LR will have to spend some time re-creating the previews, and that is a small price to pay.
> 
> Hal


Thanks Hal, this confirm my approach is right!


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## Drolleddu (Nov 1, 2012)

Brad Snyder said:


> ... Recognize that Previews are used only in the Library module. They have no use or accelerating function in the Develop module...



Thank you also to you, Brad. This is interesting and new to me, good to know..... :mrgreen:


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## Mark Sirota (Nov 3, 2012)

Brad Snyder said:


> Elaborating on Hal's correct answer. It's not required to backup up the Preview folder/package, it will auto-regenerate upon need. Recognize that Previews are used only in the Library module. They have no use or accelerating function in the Develop module.



Just elaborating slightly further on Brad's correct but incomplete answer. Previews are not used in Develop, but they are used in all of the other modules -- not just Library.


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## Brad Snyder (Nov 3, 2012)

Other modules?  LR has other modules?     LOL

Quite true, Mark, thanks for the addition.


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## MissJ (Nov 3, 2012)

I would LOVE to have some help actually using the LRPREV files if anyone is privy to information on how to extract them... try to open them on LR and says there are no files.. I'm a newbie and I have lost originals praying these files will help me! HELP ME!!


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## Mark Sirota (Nov 4, 2012)

For LR2 and LR4 I recommend Jeffrey's "Extract Cached Image Previews" plug-in. But it doesn't work for LR3, which is what your profile says you're using.

I think your best bet for LR3 is to upgrade your catalog to LR4 (download the free 30-day trial if you don't have it already), then use Jeffrey's plug-in. But you could try Marc Rochkind's LRViewer. Marc is no longer supporting it, but it may still work for you, and it may be simpler than upgrading your catalog and installing Jeffrey's plug-in.


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## Jim Wilde (Nov 4, 2012)

Already being addressed in this thread.


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