How to Enable Text Highlighting in a PDF/A File with Acrobat Reader
Question details
The user is unable to use the highlight tool on selectable text in a PDF document, even though the file's security settings indicate that commenting is allowed.
- Product
- Adobe Acrobat Reader
- Device & OS
- not provided
- Scenario
- Attempting to highlight text or add annotations to a PDF document that may have been saved in the PDF/A archival format.
- Observed behavior
- The text highlighting and commenting tools are greyed out or completely unavailable, preventing the user from marking up the document.
Verify that the text in your PDF is actually selectable and not a flat scanned image, as highlighting requires a recognizable text layer. Additionally, check for digital signatures or certification banners at the top of the document, which permanently lock files from further modifications.
Disable PDF/A Viewing Mode in Preferences
Turn off the default PDF/A viewing mode in Acrobat Reader to re-enable editing and commenting features on archival documents.
PDF/A is a standardized format designed for long-term document archiving. By default, Acrobat Reader opens these files in a locked viewing mode to prevent any changes that might alter the document's original state. Disabling this mode allows you to add highlights and comments.
Launch Adobe Acrobat or Acrobat Reader. Click on the 'Edit' menu at the top left of the screen, and select 'Preferences' from the dropdown list (or press Ctrl+K).
In the Preferences window, look at the Categories panel on the left side and click on 'Documents'.
Locate the section labeled 'PDF/A View Mode'. Change the 'View Documents in PDF/A Mode' dropdown setting from 'Only for PDF/A documents' to 'Never'.
Click 'OK' to save the changes. Close the PDF file you were trying to edit and reopen it. The highlighting tool should now be active.
Check for Digital Signatures and Security Restrictions
Ensure the document is not digitally signed or restricted by hidden security policies blocking annotations.
Highlight and Annotate Any PDF with WPS Office
Bypass complicated viewing modes and restrictive reader settings. WPS PDF offers a streamlined, user-friendly platform that makes reading, highlighting, and annotating standard PDFs and PDF/A files incredibly easy.
- 1. Install WPS Office: Download and install the free version of WPS Office on your computer or mobile device.
- 2. Open your PDF: Launch WPS PDF and open the document you wish to read or annotate.
- 3. Apply Highlights: Navigate to the 'Comment' tab, select the 'Highlight' tool, and simply drag your cursor over the text you want to mark.
Frequently Asked Questions
Why does a PDF say commenting is allowed but I still cannot highlight text?
The file is likely being forced into PDF/A read-only viewing mode by your software, or the document contains a certified digital signature that locks the file to preserve its integrity, overriding the general security settings.
What exactly is PDF/A mode?
PDF/A is an ISO-standardized version of the Portable Document Format designed specifically for long-term archiving. It embeds all fonts and restricts dynamic content (like some annotations or scripts) to ensure the document can be reproduced exactly the same way years later.
Can I highlight text in a scanned PDF document?
Not directly. Scanned PDFs consist of flat images rather than readable text layers. You must first use an OCR (Optical Character Recognition) tool to convert the image into selectable text before the highlight tool can recognize and mark the words.
How do I know if my PDF is digitally signed?
Digitally signed PDFs usually display a blue notification ribbon across the top of the document viewer, or feature a dedicated signature panel on the left-hand side detailing the certificate's authenticity and editing restrictions.
