Corrupt previews interrupting optimisation

[Conor Masterson]

Hi
Its my first time in the DAM forums and I have been looking about for an answer to my problem with no luck.

I have been using Lightroom for a few years with great success and have over 200000 images in my catalogue with lots of collections. For the first time ever I have had a corruption problem with the preview file. I tend to always render files as 1:1 for editing and have LR set to never discard previews.

Now when I run the backup including optimise catalogue it fails and says that Lightroom has encountered a problem and will try to fix when it starts again.

I have started to discard 1:1 previews and gone back 60,000 images with no luck. The problem is a few months old and Lightroom is starting to be occasionally erratic. I used t backup and optimise regularly and have avoided any problems until now.

Can anyone please suggest a way to diagnose the problem and to rectify this without having to trash everything and start again. My setup is below.

One final note, I have backed up the preview files once and left them alone about 9 months ago so I have one old copy of that file but I don't know if it can be used to restore and update to my current state. The file is hundreds of gigs in size

Thank you

Conor Masterson


I edit on a 1920x1200 NEC monitor and I have the 1:1 preview settings set to 2048, high quality.

I am on an 8 core macpro, Snow Leopard LR3 and using an external drive to store the catalogue connected via an eSata connection. All of my archive drives are connected on separate drives too so the OS is on its own dedicated drive inside the mac and everything else is connected via eSata. It has worked very well for me, until now.

[BobSmith]

I edit on a 1920x1200 NEC monitor and I have the 1:1 preview settings set to 2048, high quality.

I don't have a definitive answer but am curious about responses as my catalog is similar to yours but running on much lesser hardware. 

One point of clarification though... the above settings are for STANDARD previews, not 1:1.  1:1 previews are created based on the actual pixels in the image file.  The preview is the exact same pixel count size as the actual image.  Making 1:1 previews speeds moving between images in the Library but it doesn't help in the Develop module (which is where I feel I really need something like that).  You may be needlessly creating 1:1 previews and that in turn may be seriously bogging down overall catalog performance.  Creating standard previews and moving the quality setting down a notch or two would probably dramatically improve your catalog performance while causing little, if any, issue in terms of evaluating images.  Your preview file would still be large but much more manageable in size.  My catalog contains about 170k images.  Most of my previews are 1440 medium quality versions.  My previews file is about 60GB.

Bob Smith

[Conor Masterson]

Hi Bob
Thanks for the speedy feedback.
As I am looking at this again and refreshing what I know from Martin Evenings books etc etc It did occur to me that what I was doing may be overkill. I am going to ditch all the 1:1 from the entire archives now and maybe in a week or two I will have a better idea about answering your question. As it is now having 1:1 makes editing faster. I will also set to delete 1:1 after 30 days too

Basically I didn't know that the standard sized previews are enough for editing and as I looked at the recent images where I had ditched the 1:1 there seems to be no difference for basic browsing.

One other thing though is that I recently discovered you can put the camera raw cache somewhere else that Lightroom uses and I have just put mine on an internal raid so this will also influence things. I'll come back and let you know what I think in due course.

One other thing I am wondering about now is that I convert all of my canon work to DNG creating a  large jpeg preview at high quality. I wonder if these help lightroom if I have to re-import. Have you any ideas?

Thanks again

Conor Masterson