Some - not all - photos appear as gray in Library and Develop

[yardage]

I've uploaded images but only some are appearing. I've taken steps recommended elsewhere (uploaded current version of LR; changed the display profile) but they still don't appear. If I go to import them again, LR says the files already exist. Incredibly frustrating and seem to be getting nowhere. Any suggestions?  

{Moved from Lightroom Cloud to Lightroom Classic Forum by Moderator} 

[SeanMcCormack]

Does generating previews manually make a difference? Library menu>Previews>Build Standard Size Previews

[johnrellis · Accepted solution]

Your screenshot indicates that those gray thumbs don't have any associated metadata (filename, dimensions, EXIF, etc.). This indicates a likely problem with the catalog itself, not with the preview cache, graphics drivers, or display profile. There were a number of reports about this a year or two ago.

As a first step, ensure you're on the current version (10.3): Do Help > System Info, and if you're on an earlier version, do Help > Updates.

At least one person reported that right-clicking a folder in the Folders panel and doing Synchronize Folder go rid of the problem thumbnails:

https://community.adobe.com/t5/lightroom-classic/solid-grey-image-previews-in-library-after-reimport... 

And for some others, exporting all but the grey thumbnails as a new catalog worked:

https://community.adobe.com/t5/lightroom-classic/grey-thumbnails-that-can-t-be-deleted/m-p/10356232#...

If those don't help, try posting in the official Adobe feedback forum with all your details, including the screenshot and the first ten lines of Help > System Info. (Don't just link back here, since experience shows that Adobe employees often won't follow the links.)  In your post, address it directly to Adobe employee Rikk Flohr ("@Rikk"), who can sometimes get your catalog run through an internal Adobe fix-it script.

[yardage]

Many thanks Sean - synchronising the folders fixed it. Much appreciated. 

R