Hi,
from time to time I get a preview trashed like this - the three horizontal bars/stripes across the picture are the artifacts added by Lightroom. Fortunately, ARW file was untouched. The pattern may be different. This is preview in Library, Loupe in library looks the same, Develop - as well. Discarding / rebuilding views on this picture alone bring no change.
This happened more than once and is utterly irritating and scary. And if there are reasons to immediately switch to another software - being afraid that my photos might get damaged, and having lost the trust in the soft, is definitely one on top of the list.
Any ideas what is the reason? How to deal with it?
I have got Lightroom 6.12 (minor version is not significant, it keeps repeating regardless) on Mac with Sierra.
cheers,
Stan
28
Replies
Hardware corruption typically only affects the raw file, and not the embedded preview, which is what you will see in most other applications that can't render the raw file itself.
If your hard drive and RAM are sound, the corruption is most likely happening when transferring the files from camera to computer.
It could be a faulty camera card, USB cable/connection, or card reader.
Lightroom cannot cause corruption since it only reads the raw files.
And your screenshot did not come through, you have to reply using a web browser to post a screenshot.
Click the image icon in the toolbar to insert an image.
Hi,
confusion progresses. I managed to attach the pictures and to conduct some other experiments.
1. The left one is in the grid view.
1.1. From what I had read, LR uses a preview in Library module to speed up/avoid reading the whole RAW file (which in my case has approx 25MB). These files are stored locally in Lightroom Catalog Preview.lrdata.
1.2 When I open a bigger view, still in Library module - I see the same picture with the same stripes, just bigger.
1.3 Right now I cannot open RAW file, because file is on NAS at home, and I am not. I get these pictures, which is yet another proof that it is not RAW (ARW) that is read (and I hope it is not true that it is damaged).
2. to the right you have mac os X preview
2.1. To be precise: I open it using "Quick Look" (pressing space in Finder). It opens and reads actual RAW file (below is how I checked it)
2.2. I opened an Activity Monitor and looked at process (Quick Look UI Helper) and how much bytes it read. And its reads ~25MB, so the whole file. IT is also noticeable from the UT, as there is some time between pressing a space and an actual image available on screen.
3. I experience no other problems on my mac, no damaged files, no random crashes, nothing. If there would be RAM issue, what is likelihood that it happens only in LR? If there is a disk issue, the same question (not to mention that actually two storages are involved NAS and local SDD).
4. I use RAID on my Synology NAS, which BTW reports no single issue with disks.
cheers,
s
Thanks and sorry. I have an impression (and a bad conscience) I had been
too harsh. Please accept apologies.
Thanks for additional thoughts. As for the exports - here is a riddle:
1. I copied ARW files to another folder, and created LR catalogue anew.
Among the ARW files is the one which was exported with these stripes.
2. In a new library everything is perfectly undamaged.
3. Editing and exporting from this library creates perfect JPEGs.
4. Trying to edit a file (opening a picture in a Develop module) while
exporting the files, worked without any problem.
5. In brief: I am not able in these couple of minutes to recreate the
problem. Yet it did not occur in an easy to repeat way earlier.
6. Disadvantage of the new LR-Cat: it does not have any of the
modifications / editions / keywords / geotags / collections etc. which I
had painstakingly done before 
---
7. Re my earlier test with DNG: it worked for some files, for some other
not. I still suppose it has something to do with previews.
8. Re your advise on deleting previews - I tried to do this from within LR,
and it seemed to work for some files (not all).
9. I will try deleting the files from previews.lrdata. I assumed that a
command from LR to delete them, gets rid of the files as well.
cheers,
s
2017-08-11 23:05 GMT+02:00 Per Berntsen <forums_noreply@adobe.com>:
Trashed previews - all sizes created by Per Berntsen
<https://forums.adobe.com/people/Per+Berntsen> in Photoshop Lightroom - View
the full discussion <https://forums.adobe.com/message/9761450#9761450>
Apologies accepted.
If creating a new catalog and re-importing fixed the problem, I would try the following: (not sure if it will work, but it's worth a try)
Create another new catalog, don't import anything.
Then go to File > Import from another catalog, and choose your original catalog.
That will also import all your edits and keywords etc.
We regularly get posts on this forum about a corrupted preview cache, but when it happens (in the vast majority of cases), Lightroom will either refuse to start (with an error message about the preview cache), or display blank (gray) previews in the Library. During the time I have spent on these forums (several years). I have never seen a report of Lightroom actually displaying corrupted previews.
And since the corruption also appears in exported files, I still suspect that the raw files are corrupted.
I also get the impression from one of your posts that the corruption appears in Develop as well as in Library, which also indicates raw file corruption. Develop does not use the preview cache, but creates its own previews on the fly.
And yes, you can rebuild previews from within Lightroom (Library > Previews), but to be on the safe side, I would delete the preview cache.
I have to say that your problem is confusing, and I'm not really sure what's going on - you would think that a corrupted raw file could not be fixed by converting to DNG or importing to a new catalog.
If the problem persists, I would try moving the raw files to an internal drive, or an external drive connected with a cable.
Thanks.
So here is what I have done in meantime and what I have found.
1. Copied RAW files, created a new LR catalog, imported all these file. Everything works, no damaged file. (This is just to recap, I reported it previously).
2. I followed your advice and not only forced delete of previews, but also removed previews.lrdata.
3. And this made the trick. THANKS!
Effect: Before deleting of previews I had several pictures damaged, covered with the stripes. Now - none (EDIT: thumbnails were too small to see what I noticed in step 5 below). BUT read on.
4. After deleting: the library view was being gradually reconstructed. And this is a bit troubling / hinting:
4.1. empty frames at first - so rebuilt from RAW, and this was obvious because there was no cropping, exposure adjustments etc.
4.2. adjustments started to be applied to these thumbnail previews. And here I noticed one of them "striped".
4.3. opening Develop module, opened at first a striped picture, but after a while it was refreshed - and correct.
4.4 at the moment everything seems to be ok.
To me this implies the following process:
a. RAW is ok (this is sure)
b. some transformation LR applies to the pictures make the picture "thrashed" / "striped" etc.
c. these transformation get stored in previews. Also when exporting, the transformations have to be applied to the RAW, hence the result.
Now the question is: what makes LR transformations to fail? Are they applied by multiple threads (to multiple pictures) and some elusive multi-threading / memory sharing bug kicks in? But then, I do not believe I do anything that no one else is doing. yet it seems that no one experienced something like this.
5. I exported the collection. And it is ALMOST perfect with two exceptions. 3 files that I had earlier converted into DNG are damaged as they were before. They ARW counterparts are untouched (but not in the library now , and without any adjustments).
5.1. For each of these 3 files, when I go to the Develop module, and pick whatever item from the History list, the image below appropriately reflects what I had done it it, AND on top it is covered with the stripes.
I have now two questions, one (very) big and one (relatively) small:
6.1. What is the reason for the problems I had and how to avoid them in the future (it seems, to repair them physical deletion of preview.lrdata is necessary)
6.2. how to "swap" DNG for ARW in the lib, so that I do not lose the changes I made. Well, I can eventually redo my work for 3 photos. This is not a problem. But if I can learn if it is possible to do such a "swap", would be fine.
cheers,
Stan
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