I have lots of files in different formats (mostly pdf files) and I need to check if they can be opened without errors and get a list of those that are broken.
Other than opening them all separately is there a way to find out which won't open / are corrupt?
Not really, no. Because there are so many file types it would be impossible to know if a file was corrupt without opening it. It might open without errors but still be corrupt so even that isn't going to help you. You could try a general file opening solution like KeyView which can open most file formats. If it fails then chances are the file is corrupt.