Fix Corrupted Text Characters After Combining PDFs in Acrobat
Question details
Users are experiencing issues where merged PDF documents display corrupted text, showing up as boxes, shapes, or gibberish.
- Product
- Adobe Acrobat Pro DC / Acrobat X
- Device & OS
- not provided
- Scenario
- Combining or merging multiple source PDF files into a single PDF document.
- Observed behavior
- After the merge process is complete, the resulting PDF file displays unreadable characters, boxes, or shapes instead of the original text content.
Before applying fixes, ensure you have kept the original, uncombined source PDF files and check if you have the fonts used in the documents installed on your system.
Recreate PDFs with Fully Embedded Fonts
Use this solution to ensure that all custom fonts are permanently attached to the source PDFs before combining them.
Corrupted characters during a PDF merge usually happen because the original documents use custom fonts that are not embedded. When Acrobat combines them, it fails to find the font data and substitutes it with boxes or gibberish.
Open the original documents (e.g., Word, Excel, or PowerPoint) that were used to create the problematic PDF files.
Go to File > Options > Save (in Microsoft Office) and check the box for 'Embed fonts in the file'. Then, go to File > Save As and select PDF.
Click on 'Options' in the Save As dialog and ensure 'PDF/A compliant' is checked, as this forces font embedding. Save the new PDFs.
Open Adobe Acrobat, go to Tools > Combine Files, select your newly created PDFs, and merge them. The text should now display correctly.
Flatten the Source PDFs Using Print to PDF
This method converts text and formatting into a flattened layer, removing encoding conflicts before the merge.
Optimize the PDF to Fix Encoding Errors
Running the PDF Optimizer can clean up damaged document structures and fix underlying encoding conflicts.
Combine PDFs Safely and Flawlessly with WPS Office
If you continue to experience font embedding and text rendering issues, try merging your PDFs with WPS Office. Its highly compatible PDF engine preserves original fonts, formatting, and character encoding perfectly, avoiding corrupted characters.
- 1. Launch WPS PDF: Open WPS Office and navigate to the PDF tab on the main home screen.
- 2. Select Merge PDF: Click on 'Merge PDF' from the PDF editing tools menu.
- 3. Add your files: Click 'Add Files' and select the PDF documents you want to combine into a single file.
- 4. Merge and save: Arrange the pages or files in your preferred order, then click 'Merge' to generate your perfectly formatted document.
Frequently Asked Questions
Why do my fonts change into boxes when merging PDFs?
This usually happens when the source PDFs use unusual custom fonts that aren't fully embedded. During the merge process, the software cannot locate the required font data, so it substitutes the missing fonts with default characters, blank boxes, or gibberish.
How can I check if fonts are embedded in my PDF?
Open your PDF in Adobe Acrobat or WPS PDF, navigate to File > Properties, and click on the 'Fonts' tab. If the fonts are correctly included in the document, you will see '(Embedded)' or '(Embedded Subset)' listed next to the font names.
Does printing to PDF reduce the quality of my document?
Printing to PDF (flattening) converts interactive elements and sometimes text into base images. While it resolves merging errors and encoding conflicts, it removes text editability and might slightly affect the crispness of the text at high zoom levels.
