This article explains common messages and how to resolve them.
Could not open a PDF
This means the app could not read the selected file as a PDF.
- Make sure the file is a valid PDF.
- Try opening the file in Preview to confirm it is readable.
- If the file is on an external drive or cloud folder, copy it to your Mac and try again.
Choose a valid page or page range
This means the selected page number or range is outside the PDF page count.
- Check the page count shown after loading the PDF.
- Use page numbers starting at 1.
- Make sure the From page is not greater than the To page.
Some files were skipped
This appears when unsupported files are added to Create / Merge PDF.
- Add only PDFs or supported image files.
- Check the file extension.
- Convert unsupported files to PDF, PNG, JPEG, or TIFF before merging.
Could not read an image
This means macOS could not read the image file.
- Try opening the image in Preview.
- Export or convert the image to PNG or JPEG, then try again.
- Check that the file is not damaged.
Could not create a PDF page from an image
This means the image was opened, but could not be converted into a PDF page.
- Convert the image to PNG, JPEG, or TIFF and add the converted file.
- Try reducing very large image dimensions before merging.
Could not write the output file
This means the app could not save the result to the selected location.
- Choose a different output folder, such as Desktop or Documents.
- Make sure you have permission to write to the selected location.
- Check that the destination drive has enough free space.
- If replacing an existing file, make sure it is not open in another app.
Exporting an image format is not supported
This means the selected image format is not available through macOS image export on your system.
- Try PNG or JPEG.
- Update macOS if an image format should be supported but is failing.
Drag and drop does not add files
- Make sure you are dragging files, not folders.
- For splitting, drag a PDF file into Split PDF.
- For merging, drag PDFs or supported image files into Create / Merge PDF.