Skip to main content

Troubleshooting PDF Split & Merge

Updated

Troubleshooting PDF Split & Merge

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 with Quick Look in Files or with Preview on Mac to confirm it is readable.
  • If the file is on an external drive or cloud folder, download or copy it locally 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 on Mac or Merge on iPhone and iPad.

  • 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 the app could not read the image file.

  • Try opening the image in Files or another image app, or with Preview on Mac.
  • 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.

A selected photo or dropped file could not be loaded

  • Open the item in Photos or Files first and wait for any iCloud download to finish.
  • Check your network connection and confirm that iCloud or the file provider is available.
  • Try adding the item again with Add Photos... or Add Files....
  • If the problem continues, export a local PNG or JPEG copy and add that copy.

Could not write the output file

On Mac, this means the app could not save to the selected destination. On iPhone and iPad, it can also mean the app could not generate its temporary output before showing the Files export sheet.

  • Choose a different destination, such as Desktop or Documents on Mac or a local folder in Files on iPhone and iPad.
  • 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

iPhone and iPad support PNG and JPEG image export. Mac also supports GIF, TIFF, BMP, and JP2 when those formats are available on the system.

  • Try PNG or JPEG.
  • Update macOS if an image format should be supported but is failing.

A file in Files or iCloud Drive cannot be opened

  • In Files, tap the cloud download icon and wait for the download to finish before selecting the file again.
  • Check your network connection and confirm that the file provider is signed in.
  • Try copying the file to On My iPhone or On My iPad, then import the local copy.
  • Confirm that the file uses one of the supported iPhone and iPad formats.

An export does not appear in Files or iCloud Drive

  • After processing finishes, complete the Files export sheet. Canceling it does not save the generated files.
  • Choose a destination under On My iPhone, On My iPad, or iCloud Drive in the export sheet.
  • Check that the device and selected cloud location have enough free space.
  • Wait for iCloud Drive to finish syncing, then reopen the destination folder in Files.
  • Try exporting to a local folder to determine whether the issue is specific to the cloud provider.

Already optimized

This appears when compressing a PDF would not make it at least 10% smaller, so no file is saved. It is common for PDFs that contain mostly text. Try the Smallest File quality level, or keep using the original PDF.

A PDF is password protected

PDFs that require a password to open cannot be compressed. Remove the password in another app, such as Preview on Mac, and try again.

A button or list control is unavailable

Import, reorder, remove, and export controls are temporarily unavailable while the app is loading, importing, or processing files. Wait for the current operation to finish, or use the cancel button shown with processing progress.

Drag and drop does not add files

  • Make sure you are dragging files, not folders.
  • For splitting, drag a PDF file into Split PDF on Mac or Split on iPhone and iPad.
  • For merging, drag PDFs or supported image files into Create / Merge PDF on Mac or Merge on iPhone and iPad.
  • For compressing, drag a PDF file into Compress PDF on Mac or Compress on iPhone and iPad.
  • On iPhone or iPad, make sure the source app supports dragging the selected file. If not, use Choose PDF... or Add Files....