How to Fix Garbled Chinese Text and Box Characters in Acrobat PDFs
Question details
The user needs to fix an issue where text suddenly appears as garbled characters or square boxes in Adobe Acrobat, particularly after merging or inserting pages.
- Product
- Adobe Acrobat
- Device & OS
- not provided
- Scenario
- Combining, merging, or inserting pages from different PDF files that contain Chinese text or specific fonts.
- Observed behavior
- Text suddenly turns into square boxes or garbled characters due to missing or subset-embedded font conflicts across the merged files.
Ensure you have access to the original source documents (such as Word or PowerPoint files), as fixing subset-embedded font errors often requires exporting the PDF again with different font settings.
Recreate the PDF with Full Font Embedding
The most effective way to resolve box characters and garbled text is to re-export the PDF from the original source file while ensuring all fonts are fully embedded.
When PDFs are created with subset-embedded fonts, they only store the specific characters used in that document. Merging multiple PDFs with different subset fonts often leads to character conflicts, resulting in garbled text or boxes.
Open the original source file (e.g., Microsoft Word, Excel, or WPS Writer document) that was used to create the problematic PDF.
Go to 'File' > 'Save As' or 'Export', and select PDF as the output format. Before saving, click on 'Options' or 'More Options'.
Look for the setting related to fonts, such as 'Embed fonts in the file' or 'ISO 19005-1 compliant (PDF/A)', and ensure it is checked. This forces the application to embed the entire font library into the PDF.
Save the new PDF. Repeat this process for all documents you intend to merge, then combine the newly generated PDFs to avoid subset font conflicts.
Use Acrobat Preflight to Fix Font Embedding
If you do not have the original source files, you can attempt to embed the missing fonts directly within Adobe Acrobat using the Preflight tool.
Merge and Edit PDFs Without Font Issues Using WPS Office
WPS Office features a robust, built-in PDF editor designed to handle complex font embedding automatically. When you merge or edit PDFs in WPS Office, it manages font resources seamlessly to prevent garbled text and missing character boxes.
- 1. Download and install: Download and install WPS Office for free from the official website.
- 2. Open PDF Tools: Launch WPS Office and navigate to the 'PDF' tab to access the suite of PDF editing and merging tools.
- 3. Merge PDFs safely: Click on 'Merge PDF', select the files you want to combine, and let WPS handle the background font mapping automatically.
- 4. Export without errors: Save the newly merged PDF. The text will render correctly without subset font conflicts or square boxes.
Frequently Asked Questions
What causes subset-embedded font errors in PDFs?
Subset embedding means only the specific characters used in the original document are saved within the PDF to reduce file size. When you merge this PDF with another file using the same font but different characters, the PDF reader cannot map the missing characters, resulting in square boxes or garbled text.
Why does Chinese text often turn into boxes when merging PDFs?
Chinese fonts have thousands of characters, so PDF creators almost always subset them to save space. When multiple PDFs subset the same Chinese font differently, merging them causes Acrobat's font dictionaries to conflict, rendering the characters as unreadable boxes.
Can I fix the garbled text if I don't have the original Word document?
It is difficult but sometimes possible. You can try using Adobe Acrobat Pro's Preflight tool to 'Embed missing fonts', or print the problematic PDF to a virtual PDF printer (like 'Microsoft Print to PDF') to flatten the file, though flattening removes text searchability.
