Why a PDF Can't Be Merged or Shows an Error
Key points
- Password-protected (encrypted) PDFs can't be loaded
- A damaged PDF can sometimes be fixed by re-saving it in its original app
- If too large, compress first
If merging shows an error, these are the likely causes.
1. A password is set
PDFs with a password or editing restrictions often can't be loaded. Ask the creator for a version without a password, or remove the password first.
2. The PDF is damaged
For example, a download that stopped halfway.
- Download it again
- Re-save it as a PDF from the original app (such as Word)
- Open it in another PDF viewer to check it opens properly
3. The file is too large
PDFs over several tens of MB can fail when the device runs out of memory.
- Compress the PDF first
- Merge in two rounds instead of all at once
4. The file isn't really a PDF
A file ending in .pdf can still be something else. If it is an image, convert it with "Photos to PDF" first and then merge.
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Use "Merge PDFs" (free)Tools that go well with this
- Compress PDF: Shrink a PDF to fit under a size you choose, for upload limits.
- Add Page Numbers to PDF: Add page numbers to a PDF, choosing position and style.
- Extract or Delete PDF Pages: Keep only the pages you need, or remove the pages you don't.
More guides for this tool
- How to Combine Several PDFs into One (Phone and Computer)
- How to Choose the Order When Merging PDFs and Rearrange It Later
- What to Do When a Merged PDF Becomes Too Large
- Tips for Combining Job Application Documents into One PDF
- How to Combine Photos and PDFs into One File
- Safety Checkpoints When Choosing a PDF Merge Tool