Odd problem with thumbnails

[jonz]

This is probably just some setting I am missing. I have a large database of images (about 250k) that is mostly organized in hierarchical date order. Three hard drives are used for storage, one a USB external and another SSD external, and an internal SSD.
The problem is that thumbnails are not appearing for several years worth of images on the USB external drive. These files start with a specific year and then all the directories that follow on this drive have the same problem, so it's as if there was a sequential update scan that failed.  The program icon appears in place of the image thumbnail. If I force a rescan of the involved directories the thumbnails flash on screen but then disappear. Send to viewer works but show all versions or the popup representations of the files in different directories in the tree list do not work.
I've also done a diagnostic scan of the database and no errors are reported. It's just this  one period of about 3 years (representing about 15% of the images) that I'm having the problem with. Everywhere else things seem well behaved. I'm stumped.
Thank you.

[Mario]

Thumbnails are stored in the database. They are created when IMatch ingests the image.
You did not mention any specifics, e.g. the file format you are using...
You did not attach a log file

"Flash on screen"

For some formats (JPG, mostly) IMatch uses the embedded 160px thumbnail to represent the images currently being indexed. This thumbnail is only used temporary, for the file window.
From your description, and without any further info, log file etc. my guess would be that IMatch is having problems ingesting the files or extracting the image data.

Please switch IMatch to debug logging (see log file) and then repeat your test. ZIP and attach the log file.
This gives us a minimum of info to work with.

[jonz]

Enclosed is a log file where I did a rescan of one of the directories, and then after that I did a force update of the cache for the same directory. When I did the force update some of the thumbnails appeared greyed out, but then went back to the application icon when the update was done. The rescan did nothing. Both actions should be in the log file.
Thanks....

[Mario]

You have attached a screen shot. I believe what you are seeing.

It would be better to attach one of your JPEG files which produces the problem.
Or send it to support email address with a link back to this thread.

There are no errors or warnings in the log file. Just many logs about IMatch processing files in the folder

J:\jonz\photos\2019\2019-10\2019-10-18\2019-10-18_180144.jpg

successfully. Which seems odd, because IMatch only falls back to displaying the application icon (as in your screen shot, whatever the "10" stands for) when neither itself nor Windows is able to extract an image/thumbnail/preview from a file.

But this would be logged and the log file would be full or errors or warnings. IMatch things it has processed the files just fine.

[jonz]

I have sent an email with a jpg from the directory. I think you will find that there's nothing unusual about the jpg. My normal formats are RAF, jpg (from Fuji and a OnePlus phone), edited tifs, etc. I haven't changed anything there and the files have (and do) work well with IMatch. As I said, much of the database of 250k files is working normally. If I look at the preview cache in the OS it reports the same number of thumbnails as are listed in the info pane. Is there a way to know what the name of a specific thumbnail is for a specific jpg in the database? In any case, I don't see anything wrong with the cache. It's 50,819 files and 43.73 GB.
You ask about the icon (10) - it's for Silkypix Developer Studio 10, a good Japanese non-destructive image editing program with a crummy name.
As another note, the file manager displays the same jpg files and directories with proper thumbnails.

[Mario]

Thumbnails are stored in the database, not in the file system.
Only cache images for the Viewer and Quick View Panel and Slide Show are stored in the file system. See Cache

No problems processing the supplied JPEG file on two PCs and a Windows Tablet:



No errors or warnings in your log file.
No problems processing the file here on 3 computers.
Did you do a force update (!) (not just the cache) for these files with Shift+Ctrl+F5?

If this does not help:

Do a database diagnosis. Write back pending metadata (if any) for this folder.
Use the remove folder from database command (do not confuse this with Delete Folder!).
Add the folder again.

[jonz]

Force update worked to fix the problem, THANK YOU! I didn't know I could do that. Files processing very happily now.