There are several reasons why your PDF files won't open:
- The encrypted file cannot be opened and needs to be decrypted first.
- The PDF is too large for your computer to process.
- You have a PDF reader but the software is expired and needs updating.
- Your computer has a potential software conflict with PDF files.
- The file format is damaged, or it is not a standard pdf format file (could be caused by changing the format name).
Some of the reasons above are the most common reasons. If you are still having trouble opening your PDF files, make sure you download high-quality and easy-to-use PDF reader software like PDF Reader Pro Windows.