# Lightroom encountered an error when reading from its preview cache and needs to quit



## janrif (Jul 16, 2012)

Using LR4.1
Wn7 64 OS

Situation:


Had a system crash  (pilot error)
Restarting LR displays ""Lightroom encountered an error when reading from its preview cache and needs to quit. Lightroom will attempt to fix this problem the next time it launches."
I tried re-starting LR several times to see if LR could cure the error, no dice
Reading other posts on the subject, I deleted the preview folder w contents
Restarting LR displays same error

I assume I have to have LR re-build previews but can't if LR continues to force a shut down. 

Now what? 
Thanks very much.


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## missingelement (Jul 17, 2012)

Did you delete you cache folder or your preview file with your catalog?


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## janrif (Jul 18, 2012)

preview file with catalog


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## Victoria Bampton (Jul 18, 2012)

Hi janrif, welcome to the forum!

Try moving the catalog to a new location before you rebuild the previews.  I've seen it give false error messages once in a blue moon.


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## janrif (Jul 18, 2012)

Thanks Victoria. 
Too late. 
I keep my catalog on drop box but should probably change move it to a HD w backup to drop box. 
Does preview folder have to be in same location, i.e. side by side w catalog dB?


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## b_gossweiler (Jul 18, 2012)

janrif said:


> Thanks Victoria.
> Too late.
> I keep my catalog on drop box but should probably change move it to a HD w backup to drop box.
> Does preview folder have to be in same location, i.e. side by side w catalog dB?



Yes.

Beat


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## Stace Hart (Jul 1, 2015)

hi guys I have just encountered this problem on my LR 5.6version. any idea how I can open my old catalog, as I have just recently been away. It has never happened before in the 2 years I have been using lightroom. so im kinda stumped. Cheers


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## clee01l (Jul 1, 2015)

Stace Hart said:


> hi guys I have just encountered this problem on my LR 5.6version. any idea how I can open my old catalog, as I have just recently been away. It has never happened before in the 2 years I have been using lightroom. so im kinda stumped. Cheers


Welcome to the forum.
The problem being discussed here was a corrupted Previews folder with a specific error message.  Is that your problem too?  Or is your LR catalog simply failing to open (possibly due to not being closed properly)?


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## Stace Hart (Jul 1, 2015)

clee01l said:


> Welcome to the forum.
> The problem being discussed here was a corrupted Previews folder with a specific error message.  Is that your problem too?  Or is your LR catalog simply failing to open (possibly due to not being closed properly)?



Same problem


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## Jim Wilde (Jul 1, 2015)

Have you tried deleting the previews cache? In the same folder as the catalog will be the previews cache, which is a folder with the same first part of the catalog name, and ending with "Previews.lrdata". Rename this folder, then start Lightroom, which should start OK. A new previews cache will be created automatically, after which you can delete the corrupted renamed previews cache.


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