An issue popped up where some of my pictures are displaying the message 'file could not be found' while in Develop mode. The files haven't been moved or deleted, I can still see them in the same location by browsing to them in explorer. Switching to Library mode, there is no exclamation or question mark on the file thumbnail to indicate that it was unable to locate it, so I am not given the option to locate it manually. Right-clicking on the file and selecting to open file location, it correctly opens the folder in my documents where it is located and the file is highlighted. Right-clicked on the folder in Library and selected to synchronize, issue still persisted. Selected option to 'Find All Missing Photos', photos I am having trouble with did not show up in list. Would it be possible that the files that are present but not editable in Develop are corrupt? Or is there an option I'm missing on how to manually fix the missing files in Develop mode.
File could not be found is a very specific message, and has nothing to do with file corruption. First, I would restart the computer and see if the problem goes away. If it doesn't, show us relevant screen captures.
Any chance the drive containing the files went into a power-saving sleep mode?
Turns out my documents were being redirected to our file server, had a network issue with a switch that temporarily dropped connection. Once connection was back up was able to access files but I guess LightRoom still thought the files were offline but showed the drive online. Rebooting the computer resolved the issue, thank you.