media (MIME) type could not be detected

I am receiving the following error message when trying to upload PDFs. "File Upload: The file '... .pdf' could not be ingested because its media (MIME) type could not be detected."

We recently transferred to a new server and since then we were able to upload one PDF to the new server location, yet now we continuously get this error message when trying to upload new items. Our site is still active on the old server and I was able to upload files there so I'm pretty sure it's not an issue with the files...? Has anyone else come across this?

Omeka's file type detection mostly depends on type definitions and detection libraries provided by the underlying system. Since the problem cropped up after changing servers, I'd say the new server's file-detection setup isn't quite right.

The basic package that handles this stuff is usually just called "file," and you generally want the most up-to-date version available from your package manager. The other big piece of the puzzle is usually PHP's Fileinfo extension. That's automatically included in PHP 5.3, but has to be manually installed as an extra extension for PHP 5.2.