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Question

Trashed previews - all sizes

Forum|Forum|8 years ago
August 9, 2017
6 replies
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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

This topic has been closed for replies.

A

Anonymous

Sorry, but this is not hardware. Problem was in Camera Raw.

After changing LR setting (turn off GPU and change cache size) with support i can import again without problem.

Per Berntsen

Community Expert

That's strange.

I downloaded the two files, and the corruption is showing in Lightroom, and it doesn't go away when I turn off the GPU.

I also opened the files in RawDigger, which also shows the corruption.

However, the embedded jpgs are not corrupted - which is typical for hardware corruption of raw files.

Are you sure that you are not looking at the jpgs? The jpgs you posted on Google Drive do not show corruption either.

A

Anonymous

You must remove item, clean cache and do new import.

DSC04414-idc.JPG - from Image Data Converter.

Support set this settings.

After this i removed corrupted files, purged cache, restarted LR and imported again

A

Anonymous

You can see ARW here: share - Google Drive

Per Berntsen

Community Expert

This is no doubt corruption caused by failing hardware.

See post 4 in this thread.

A

Anonymous

I have same problems.
I check ARW in Sony PlayMemories Home - all ok, but when i open in LR or QuickView - file corrupted.

Export from LR:

Same file from Image Data Converter (Sony):

S

sbochnakAuthor

Known Participant

@Per:

At first I was to leave it, but in my quest for useful help I cannot.

0. I must say I do not understand how can you state anything about something you in your own words do not know?

How should it help me, or anyone else reading this post?

I used to be a software engineer by education, and by practice. And here are some arguments why this is relevant:

1. I do not believe a professional SE would ever write a program reading the whole file (RAW, uncompressed), when it is enough to read only part of it (embedded JPEG, which by definition is compressed and is much smaller).

2. You say you do not know Quick View. But do you know Activity Monitor? The tool I used to check how much data a process (Quick View) had read from HDD. The tool works at the level of operating system, through which all the processes go to read the files. The number of bytes read I provided has nothing to do with "reporting the file size" you are referring to (BTW, where did you get it from?). This is the number of bytes ACTUALLY READ from the disk.

3. By saying "JPG preview is full size" what do you mean: it has 25MB? or a displayed picture has the original resolution? You seem to suggest it has the same size, hence QuickView would read 25MB, yet anyway it would read the JPG and not RAW. Well. The only problem is, that if JPG was the same size (on disk) like the RAW (in other words, if it was uncompressed) then the file itself would be of double size: one RAW + JPG. Which of course is not the case.

4. LR does not touch original files. I know. And - as I wrote - ARW is not damaged (despite what you keep repeating). Instead, LR stores working copies named previews, in "files" .lrdata. And these are apparently damaged.

5. "WiFi is the cause of the proble, LR may not even be designed for it" - Oh, God! How does design for WiFi differ from design for - say - ethernet? Are you aware of OSI layers of network? Which means that above IP layer the app that uses communication is not aware what physical media transfers the signal: cable, optical cable or radio wave (Wi-Fi), and that any connection may get lost? Which requires additional checks / management etc. at the higher layers?

I am sorry to say, but this reply was not only not useful, it is also misleading to other possible readers. And the more misleading that you seem to boast title of Adobe Community Professional. Maybe, generally good practice is if one do not know something, one stays quiet?

Per Berntsen

Community Expert

Since I'm neither a software engineer or a Mac user, I'm not going to argue with you.

Hopefully a Mac user can chime in and help you better than I can.

Just a couple of things -

By saying "JPG preview is full size", I mean the same pixel dimensions as the raw file. The file size of the jpg is obviously much smaller than the raw file, and is included in the total file size of the raw file.

I exported files as JPEGs and got even more trashed ones - both as output and within Lightroom.

The exported jpgs are derived from the raw files, not Lightroom's previews. So if they have the same corruption, it indicates that the raw files are corrupted. (Develop uses its own previews, which are created in real time)

To check if the LR previews are corrupted, you can delete the preview cache, the previews will be rebuilt as you browse the Library.

With Lightroom closed, go to the folder that contains your Lightroom catalog, and delete the file whose named ends with previews.lrdata

There is also a plugin that extracts the previews (designed for situations where the originals are lost), you can use it to examine the previews as individual files. Jeffrey Friedl's Blog » Jeffrey’s “Extract Cached Image Previews” Lightroom Plugin

S

sbochnakAuthor

Known Participant

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

I

intelligent_neighborsFA21

Inspiring

Check every stage of your workflow by making for example a new temporary catalog. Import that same image and see if he also had those damages.

Eliminate stage per stage what could be the problem. On another computer with another catalog; does the problem also occurred?

If you don't use WIFI; by using a cable; does the problem occured?

The file seems to be perfect. Have you open the file in Photoshop?

Let me know?

S

sbochnakAuthor

Known Participant

I devised another experiment: I converted the file to DNG. As a result the picture looks correct right now.

Unfortunately this proves nothing. I cannot be sure that this will not happen later, as in other cases. In fact I had an impression it was not related to the workflow itself - its steps. It was happening when I returned to the folder or collection to continue editing.

And yesterday it happened to other pictures than the shown one in the following situation:

1. I was exporting a collection of pictures as the highest quality JPGs AND

2. at the same time I double clicked the picture in the library view or maybe pressed D to get it into Development - not sure now

3. this resulted in the subsequent picture thrashed in a similar way like the first one.

4. What I also noticed that when opening the picture after a short while its histogram was changing (and pic as well) and then the thrashing was appearing.

Could it be that there is a multithreading problem? One thread exports the pictures, the other edits (or prepares for editing)?

Per Berntsen

Community Expert

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.

I don't use a Mac, but I doubt that Quick View renders the raw file.

It will of course report the correct file size, but will most likely display the embedded jpg preview.

All raw files contain an embedded jpg preview, and I believe that they are full size for most cameras.

And again, Lightroom doesn't touch your raw files, and I don't think it's even possible that it could cause any corruption.

As suggested by others, try using a cable (or preferably a card reader) and see if that makes any difference. I suspect that using WiFi is the cause of the problem, Lightroom may not even be designed for it.

I have no idea why converting to DNG fixes the problem - if it does, good for you.

But the real solution could well be to stop using WiFi.

S

sbochnakAuthor

Known Participant

Update:

I exported files as JPEGs and got even more trashed ones - both as output and within Lightroom.

I guess I am maturing to switch from LR.

Hal P Anderson

Inspiring

Couldn't see your screen print, but it sounds like you have hardware problems--either your hard drive or your RAM is failing. Run diagnostics on both.

Hal

S

sbochnakAuthor

Known Participant

Hi,

I ran diagnostics - nothing. Also, I do not experience any problems with

any other apps.

I rebooted the machine, relaunched LR - and the picture is damaged exactly

as it was. If this was a memory problem, it should randomly appear and

change after rebooting (not very likely that the same address would be

reused and same patter would be repeated).

What are your other ideas?

I attach a print screen. Left top you see the Grid view of LR, and the

damaged photo. To the right you can see the preview of the original file.

BR,

s

2017-08-09 21:03 GMT+02:00 Hal P Anderson <forums_noreply@adobe.com>:

Trashed previews - all sizes created by Hal P Anderson
<https://forums.adobe.com/people/HalPAnderson> in Photoshop Lightroom
- View the full discussion
<https://forums.adobe.com/message/9756188#9756188>

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