Fix Cannot Highlight Text in Adobe Acrobat Pro
Question details
The user is unable to use the Highlight tool to mark text within a PDF document using Adobe Acrobat Pro.
- Product
- Adobe Acrobat Pro
- Device & OS
- not provided
- Scenario
- Attempting to annotate or highlight specific text in a PDF document for review or study purposes.
- Observed behavior
- The Highlight tool fails to select or mark the text, often because the document is a scanned image, has restricted security settings, or contains non-selectable elements.
Before modifying any settings, use the standard Selection tool to click and drag over the document. If it acts like an image and you cannot select individual words, you are dealing with a scanned PDF.
Run OCR to Recognize Text in Scanned PDFs
If the document is a scanned image, you must convert the image into selectable text using Optical Character Recognition (OCR) before highlighting.
Acrobat Pro includes a built-in OCR tool that scans images and turns them into editable and selectable text. This is the most common fix for highlighting issues on scanned documents.
Open the problematic PDF in Adobe Acrobat Pro, click on the 'Tools' tab at the top left, and select 'Scan & OCR'.
In the secondary toolbar that appears, click on 'Recognize Text' and choose 'In This File' from the dropdown menu.
Click the 'Recognize Text' button to start the process. Wait for Acrobat to process the pages.
Once the OCR process is complete, switch back to the Highlight tool and drag your cursor over the newly recognized text.
Check Document Security and Permissions
Some PDFs have security restrictions applied by the author that prevent adding comments or highlights.
Highlight Text and Perform OCR Easily with WPS Office
WPS Office includes a powerful, user-friendly PDF editor. If you are struggling with restricted or scanned PDFs in other software, you can easily open, recognize, and highlight text using WPS PDF.
- 1. Open your PDF: Launch WPS Office and open your scanned or un-highlightable PDF document.
- 2. Use the OCR Feature: Navigate to the 'Tools' tab and click on the 'OCR' button to convert the scanned image into selectable text.
- 3. Select the Highlight Tool: Once the text is recognized, go to the 'Comment' tab on the top ribbon.
- 4. Highlight Your Text: Click the 'Highlight' icon and drag your cursor over the text you wish to emphasize.
Frequently Asked Questions
Why is my PDF text selecting as a large block instead of individual words?
This usually happens when the PDF is saved as a flat image or is a scanned document rather than a text-based file. You will need to run an OCR (Optical Character Recognition) tool to make the individual words recognizable.
How do I know if my PDF is locked or restricted from highlighting?
You can check the document's security settings by going to File > Properties and viewing the Security tab. If 'Commenting' is marked as 'Not Allowed', the author has restricted the document, and you cannot highlight the text without unlocking it.
Can I highlight text in a secured PDF without the password?
No. If the document creator has securely restricted commenting and editing, you must have the original permissions password to unlock the file and enable annotation tools like the highlighter.
