Why Can’t I Highlight Text in PDF? Here’s 9 Quick Fixes

  Kanishka Vohra
Written By Kanishka Vohra
Anuraag Singh
Approved By Anuraag Singh
Modified On September 16th, 2025
Reading Time 15 Min Read

PDFs have already conquered the business workflow, bringing ease to professionals to handle chunks of digital documents instead of paperwork. Similarly, the traditional markers are replaced by text highlighters. Picture this: what if you can’t highlight text in PDF file? This issue might impact your workflow. Here, you certainly search for why can’t I highlight text in PDF. Follow the guide to discover the reasons for this and the troubleshooting tips to overcome this pesky issue. This way, you can effortlessly highlight or make your document selectable.

Why Can’t I Highlight Text in PDF?

Whether it’s paper or digital documents like PDFs, highlighting pens or markers are beloved by everyone. Making the text look eye-catching, or even selecting the keynotes, allows you to mark important data easily.

Today, PDFs are the constant medium for sharing, storing, or reading information. Unlike papers, PDF offers many features to manage data, especially the PDF highlighter, which is among the translucent and handy options for text selection with different colours.

Unfortunately, errors such as can’t highlight text in PDF, or my highlight on my PDF won’t highlight just one line, can cause a delay in the workflow. Below are possible causes why won’t let highlight text in Adobe PDF:

  • PDF is Image-Based or Scanned: If your PDF document is created by scanning, the text is stored in image format instead of selectable or editable text. In this case, you experience the issue like can’t highlight text PDF as the document contains text in picture format.
  • Secured PDF Document: Sometimes, PDFs are secured with advanced restrictions or security. The permissions, such as text highlighting or editing, are controlled by owners to prevent unauthorized action on the files. Hence, you should remove PDF restrictions to access the data.
  • Corrupted PDFs: Corrupted PDF files are typically damaged, incompatible, or incomplete, containing errors due to file transmission, storage, or creation. This reason triggers the issue of can’t select text in PDF file.
  • Read-Only Mode: If the PDF file is opened in read-only mode, it certainly controls actions like highlighting and sharing of the PDF file. Hence, you need to turn off the permissions that make PDF read only to ensure easy text selection.
  • Outdated Version of PDF Highlighter: Using the older version of PDF Highlighter doesn’t support features like text highlighting. It unable to select the text in the PDF document effortlessly.
  • Flattened PDF: If you’re constantly facing the issue of not being able to highlight in a PDF file, it may occur if the PDF file is flattened. A flattened PDF restricts viewers from basic interactions, such as text highlighting and annotations. It is unable to highlight text in PDF as the content is converted into an image.

Overall, these are the most typical reasons why can’t highlight text PDF. Certainly, you might face any of these causes when unable to select the content in the document. Now, let’s walk through the troubleshooting fixes.

Instant Solution for “Highlight in Acrobat Stopped Working”

Sometimes, you might address the problem like “wont let highlight text in Adobe PDF or highlight in Acrobat stopped working”.
highlight in acrobat stopped working
It mainly occurs when Adobe Acrobat not responding or contains security measures. If the protection stops you from text highlighting in PDF, below are the right tool to fix can’t highlight text in PDF:

  1. Download the SysTools PDF Unlocker Tool on your machine (Windows or macOS).
  2. After installation, select “Add Files or Folder” to upload the problematic PDF files.
  3. In the current interface, go to Password > enter passkey.
  4. To enable PDF highlighting > tab Save radio icon.
  5. Use the Change and set the right location for the output PDF.
  6. Instantly, press the Unlock button to disable protection.
  7. Now, open the PDF > select or highlight any text in the PDF.

Watch a Video Tutorial on “PDF Won’t Let Me Highlight”

Here, watch a quick tutorial on why I can’t highlight text in PDF document. It provides a complete overview of reasons or easy fixes:

How to Check “Wont Let Highlight Text in Adobe PDF”?

You must highlight PDF documents to mark the keynotes and summary in many circumstances. But the error “can’t highlight text in PDF” stops you from selecting the important content. Before jumping into the fixes, it is essential to check the PDF highlighting to enable it. Below are the quick techniques to check why isn’t my PDF highlighting:

  • Firstly, select the content with the cursor. And, if you can’t highlight it, this may happen when the text is scanned or imaged.
  • Use the Adobe Acrobat Pro tool to review whether the document contains protection. Before jumping into fixes, it is crucial to understand the type of security. So, open this tool, move to File > choose Properties, and pick Security. Here, search for Check Document Restriction Summary and review the protection modes.
  • Lastly, you can use a different free highlighter for PDF. Many PDF readers or PDF highlighters are available, where you can check if you are facing a similar issue of being unable to highlight text in a PDF document.

9 Simple Fixes for Can’t Highlight Text PDF Files

In the following section, we will share the best way to fix the error of can’t highlight in PDF, allowing you to enable highlighting in PDF files. Using these stepwise guides, you can easily get right to highlight or add annotations to your .pdf document. Now, let’s move to learn these easy workarounds:

  1. Turn Off Read-Only Mode
  2. Disable PDF File Security to Enable Text Highlighting Feature
  3. Repair Corrupted PDF File – Fix Font and Encoding Errors
  4. Try the OCR Tool to Read the Image-Based Text
  5. Enable PDF Highlighter Tool Instantly
  6. Update or Try a Different PDF Reader
  7. Enable Text Highlighting Using Adobe Reader
  8. Convert PDF into an Editable Document Format

Now, let’s understand these techniques one after another.

Fixes 1: Turn Off Read-Only Mode

If the PDF highlighter not working, it might happen if document is in read-only mode. This feature prevents users from making modifications like highlighting, text annotation, etc. Ensure saving the PDF document without allowing this mode. It is one of the simple yet effective troubleshooting fixes for PDF can’t highlight text. In this way, you can easily highlight and get control of the PDF file.

Fixes 2: Disable PDF Security to Enable Text Highlighting

The issue of can’t select text in PDF often happens when the file is protected with restrictions. Here, you need advanced tools like Strongly Encrypted PDF Password Remover. Using this proficient software, you can turn off the owner’s unwanted control. Moreover, it allows you to remove the protection, such as text highlighting, copying, printing, and more.

Additionally, it is a feature-packed solution that enables text highlighting in PDF documents. This way, you can highlight and select the content with the desired colour.

Fixes 3: Repair Corrupted PDF File If Cannot Highlight Text in PDF

Struggling with why can’t I highlight text in PDF, it may happen if your PDF document is corrupted or has encoding & font issues. This triggers damage to the PDF file. The major causes of this problem include file creation or transmission errors.

To repair non-standard fonts, file corruption, or broken errors, try Adobe Fixer or repair software. This tool is a game-changing solution that allows you to fix document incompatibility, making it a go-to file for highlighting, editing, and more.

Fixes 4: Try the OCR Tool to Read the Image-Based Text

If you’re constantly addressing the problem of can’t highlight text in PDF file, it mainly occurs when the document is scanned or has text in image format. Try OCR or optical character recognition tool, one of the ultimate solutions to convert the image information into selectable text.

Moreover, you can use OCR tools like Acrobat Pro, which helps you to access scanned pictures into searchable or editable text. In this way, you can highlight the text and resolve the error, like highlight text is not working in PDF.

Remember: Acrobat is not a freeware solution; instead, it is based on subscription plans. Sometimes, you might address pesky issues like Adobe Acrobat Pro not working. Hence, use this software carefully when fixing any errors.

Fixes 5: Enable PDF Highlighter Tool

Many of you might have concerns about highlight in Acrobat stopped working. This happens when you disable the highlight tool feature in your Adobe Acrobat Reader. Here, you need to ensure that the feature is enabled. It is among the simple and fast fixes to try.

Using this method, you can instantly restore the functionality of the PDF highlighter without data loss. By enabling the “Highlight Tool” option, you can just select the cursor on text and get highlighted content. This way, you can finish your work and easily share the highlighted PDF text with anyone.

Fixes 6: Update or Switch to a Different PDF Reader

If you’re seeking how to fix wont let highlight text in adobe PDF and enable highlighting, you need to update the PDF Reader. Working on an old version of Reader triggers glitches such as PDF cannot highlight text. After updating the new edition, if the problem persists, try a different PDF Reader. Below is the list of some of the latest and popular PDF Readers to make PDF Highlightable:

  • Switch to Adobe Acrobat Reader DC, the industry and professional-favored tool for highlighting or viewing PDFs. This is among the most robust and cutting-edge software utilities for anyone. It offers advanced features based on the latest trends or user needs. So, make the right choice.
  • After Adobe, choose Foxit PDF Reader if you’re seeking a convenient and cost-friendly option. It is reliable and useful for all business or professional users. Plus, it offers fast processing with highly functional features.
  • If you’re a macOS user, try Preview (a built-in macOS tool), a useful and pre-installed tool for highlighting and viewing PDF documents. However, it only works with a Mac machine. Hence, Windows or Linux users can choose the other alternatives.

Fixes 7: Enable Text Highlighting Using Adobe Reader

Facing the problem of PDF stop highlighting and wondering how to enable text highlighter in PDF. Try Adobe Reader, one of the robust tools that provides multiple features like reading, commenting, printing, and even highlighting. Follow these steps & highlight text in a PDF file with the PDF highlighter tool offered by Adobe Reader:

  1. Open your PDF document in Adobe Acrobat Reader DC.
  2. Select the Highlight Text Tool to highlight the text.
    highlight text in the pdf
  3. Click the Post button after writing the text.
  4. Lastly, Save this file at any desired location.
Fixes 8: Convert PDF into an Editable Document Format

If you’re still facing the stubborn issue of “unable to highlight text in PDF”, try to convert the PDF into an editable format. Here, you can use Microsoft Word—the most effective way to enable text highlighting in a PDF for free. In other words, it allows you to select or edit content in the document. To access the PDF to an editable format like Word, follow the steps below:

  1. Download SysTools PDF to Word Converter on your PC.
  2. To convert the document, first add PDFs via Select File.
  3. Check the Output Format, i.e., Doc > Destination Folder.
  4. Lastly, use the Convert key to access the PDF for text highlighting.

Overall, these are the easy fixes for can’t highlight in PDF. By following these methods, you can resolve the glitches and enable the PDF highlighter. However, these freeware solutions might waste your time and sometimes frustrate you. So, move down to learn the best way to fix unable to highlight text in PDF.

Bonus Tip: SysTools Pro Tool to Fix Can’t Select Text in PDF

The reason behind “why can’t I highlight text in PDF” occurs if your PDF file is secured with advanced security. To make your PDF document free from any limitations, use SysTools’ recommended PDF Pro Software, one of the most profound and standalone software solutions to remove the powerful security from the PDF file.

This tool’s prime features include batch removal of permissions like text highlighting, selecting, copying, and more. Additionally, you can remove both user and owner security restrictions from your PDF file. Most importantly, this tool helps you secure PDF elements when turning off security. This pro wizard is compatible with both Windows and Mac OS.

How to Highlight Text in PDF – Fixed Can’t Highlight in PDF

In the above outline, we have explained “why can’t I highlight text in PDF?” Using the above 9 fixes, you can enable text highlighting in the document. If nothing works, SysTools suggests a professional-grade tool that helps delete document protection settings and fix can’t select text in PDF. In this way, you can access a PDF for highlighting.

Additionally, selecting the content is among the common practices for marking notes for research, feedback, and more. Follow the steps for how to highlight text in PDF document:

  1. Install & run the SysTools Pro Software on your PC.
  2. To upload a problematic PDF > use the “Add Files” option.
    add files to upload pdf document
  3. Click the Save button and then, Change to set the path for output file.
    tab save and then, change button
  4. Now, select the Unlock icon to delete document limitations like highlighting.
  5. After this, use Adobe Acrobat Reader for PDF highlighting.
  6. Add PDF > tab, Highlight Text from toolbar.
  7. Select the necessary text for highlighting > save it.
The Bottom Line

In this workaround guide, we have shared 9 easy troubleshooting fixes for can’t highlight text in PDF files. By implementing these methods, you can highlight the PDF text with ease. Since the manual tips take time. So, try the expert-recommended solution i.e., SysTools suggested wizard to remove all kinds of PDF limitations, making your document fit for highlighting, selecting, and even text annotation without any data loss.

After removing unwanted document settings, you can resolve the error of “cannot highlight text in PDF” file. In this way, you can easily enable text highlighting or marking of the digital PDF document for research, keynotes, etc.

FAQs on Why Can’t I highlight Text in PDF

1. Why PDF Highlight Tool greyed out in Adobe Reader DC?

Ans. Due to security and protection permissions in your PDF document, the PDF Highlight tool stops working or gets greyed out. Here, you need advanced tools recommended by SysTools for deleting all the modes of protection. This way, you can restore the functioning of PDF highlighting tool in Adobe.

2. How to enable PDF highlighting feature in Adobe Reader?

Ans. To enable this feature remove commenting restrictions from PDF document and then try to highlight PDF text.

3. How to add notes to highlighted PDF text?

Ans. To add notes to highlighted PDF text select the particular text then right click on it and click the Open Pop-up Note option. After adding the text, click the Post button.

4. Why Adobe Acrobat can’t select text in PDF document?

Ans. Due to certain restrictions, a user is not allowed to select text in the PDF document.

5. Why is highlight in acrobat stopped working?

Ans. Several reasons cause unable to highlight in PDF in Adobe Acrobat. Read the common causes for the improper working of PDF highlighting tool:

  • Document Security Settings: If the PDF contains different types of protection, it may stop users from performing any actions like editing, highlighting, and accessing it.
  • Outdated Acrobat Version: An outdated edition of Adobe Acrobat may cause problems due to bugs and temporary glitches. Therefore, it can unexpectedly interfere with the highlighting feature in PDF.
  • Corrupted Installation of Acrobat: There are high chances that the error of my highlight on my PDF wont highlight just one line happens due to a corrupted installation of Adobe Acrobat Reader.

To overcome these issues, you need to update the Acrobat software regularly. Also, you can use the Adobe Acrobat Pro tool to retain the effortless functionality of the PDF highlighting feature. Besides this, change the PDF settings and access the document without security.

6. How to Make PDF Highlitable?
Ans. If you’re wondering how to highlight PDF, ensure the document won’t contain any protection. Moreover, it certainly raises the issue of “wont let highlight text in Adobe PDF”. To mitigate this error, follow the checklist to make PDF Highlitable:

  • Test the ability to select the text in a PDF document. If you can’t select in PDF, use OCR Tools, as it has image-based text.
  • The PDF might contain protection. This means you can’t highlight in a PDF document. Here, you need Pro Tools, as recommended by SysTools, to enable text highlighting in PDF.
  • If nothing works, upgrade your PDF Readers like Xodo, Mac Preview, Foxit, etc. Using these tools, you can simply highlight text in a PDF document.

To highlight in PDF, use any of these PDF Readers, e.g., Adobe Reader > Highlight Tool > select the text with the cursor > change the color > save the text highlight.

  author

By Kanishka Vohra

A Technical Analyst specializing in PDF technologies, data management and workflow optimization. I am passionate about addressing real-time technical queries and challenges, providing clear and practical solutions that help professionals manage data securely, streamline operations, and adopt the right tools for efficiency.