Is there a preflight option that I am missing that would alert a user to a link that has a missing link? For example, I have several Illustrator files that were placed in ID. InDesign displays the link normally but in fact, the Illustrator file has placed .psd files which are missing. InDesign works fine until it is time to export to PDF and then has problems. It took a bit of troubleshooting to find that the provided Illustrator files had these missing links. Since I have never come across this before, I started looking for ways to provide an alert but could not find anything in the Links panel or preflight options that might provide a warning.
Am I missing something obvious? I realize that opening the images in Illustrator provides this information but when dealing with 100s of images, often provided by someone else, it would be great to have the warning in InDesign.
When you place an Illustrator file you actually placing a PDF. InDesign has no concept of the links in an Illustrator file.
There should be no issue with outputting a PDF from InDesign with a placed AI file unless the AI file was saved with that link missing to begin with.
Bob is correct.
If you placed an InDesign file inside an InDesign file, it can detect a missing/modified file in the placed ID file.
If this happens to you often you should either plan on opening the Illustrator files and using the Illustrator Links panel, or perhaps seeing if there's a third-party preflight utility (not sure if there is one) which can do it in one step.