You were working on a PDF file in Studio. However, after finishing the translation and generating the target file, you see that, when opening the file, it doesn't contain the translation and it is incomprehensible.

1. Convert the source file to Word
2. Upload it in Studio
3. Apply either PerfectMatch with the SDLXLIFF you were working on or do a Pre-translate using the TM (if that's the case)
4. If there are target segments left empty, apply NMT and do a Pre-translate again
5. Save the target file
6. If needed, convert it back to PDF

The PDF file was not correctly processed in Studio (it might depend on the file itself, not the PDF filter necessarily).