There are a number of new errors thrown up by content validation in SP1. One of the common ones is:
Error: The tag 'image' in '0' points to a nonexistent file: 'thumbnail.jpg'.
This error happens when you have listed a file in your config.txt, and Content Manager did not find that file in the asset. It's normally seen with thumbnail images or icons, but you might also see it for any file resource you can call from config.txt, including sounds or twinkles smoke effects. The reason for this being an error is that Trainz will try to load the missing file (repeatedly, every time it needs it), and this will result in increased disk activity and degraded performance.
This can be as simple as a spelling error or typo. Is the screenshot really called 'thumbnail.jpg', or is it actually called 'screenshot.jpg'?
It could also be a misplaced file. Is it in a subfolder? If so, provide the proper path to the file relative to the base of the asset, e.g. 'art\thumbnail.jpg'.
There are a few cases of overzealous cut'n'paste where the config.txt references a file that the author never intended the asset to have. It has been accidentally copied in from another asset with a bunch of other tags, and may not be useful or relevant. In these cases, the entire line (or section) can be removed.
In a lot of cases though, the file is necessary, and simply isn't there. Despite the config.txt claiming to have a screenshot, the author simply forgot to copy it into the folder. In this case, the file needs to be created.
It should be noted that this is not the same warning as an asset that should have a thumbnails container and doesn't have one. That warning is still a warning, and has not been upgraded to an error.
