I think it would be HUGE if Adobe Lightroom automatically kept track of a file's location. It is really annoying to see the message that says "This file is offline or missing" (or something like that). Why can't the program find the file's location automatically?????
Links between the Lightroom catalog and its photos can break for a variety of reasons. One common reason is because the photos are stored on an external drive that is currently offline. If this is the case, turn on the drive or plug it back in, and Lightroom will no longer show the offline/missing message for those files.
Another common reason is because photo files were moved in the operating system instead of from within Lightroom. If this is the case, you need to tell Lightroom where the files are now located. To do this,
1. Go to Library Grid mode.
2. Click the ? icon that shows in the upper right corner of the missing file.
3. A dialog box will open and display the last known location of the missing photo.
4. Click the Locate button, navigate to the where the photo is currently located, then click Select.
5. Optional: In the Locate dialog box, select Find Nearby Missing Photos to have Lightroom search for other missing photos in the folder and reconnect them as well.
To find all files that Lightroom currently can't find, go to the Library module. Then go to the Library menu and choose Find Missing Photos to display the missing photos in the grid.