I recently installed Lightroom Classic to a new computer and it is unable to locate the original file locations. I have been attempting to manually locate and re-link to the original files (the files are still in their original location and file path on an external drive), however when I do this I go to the develop module and get the error 'file not found' but when I go back to the library window the '!' no longer appears on the thumbnail. Any advice welcome to help me re-link the files.
Are you using a slash (/) anywhere in the path to the images (file name, folder name, disk name)? That would explain it. Using a slash in a folder name is perfectly correct for MacOS, but Lightroom can't deal with it because it uses the slash as folder separator. That means that if you place an image in a folder called something like "Fall/Winter", then Lightroom thinks that this is a folder called "Fall" with a subfolder called "Winter" inside it. Obviously that will result in 'image not found'.