How to Restore the Hidden 600 DPI Warning When Highlighting PDF Text
Question details
The user needs to recover the prompt that asks to convert a scanned page to 600 DPI before highlighting text, which was accidentally hidden.
- Product
- Adobe Acrobat
- Device & OS
- not provided
- Scenario
- Attempting to highlight text in a scanned PDF document after previously selecting 'Do not show this again' on the conversion prompt.
- Observed behavior
- The 600 DPI conversion dialog no longer appears, which may prevent the text highlighting tool from working correctly on scanned documents.
Save any unsaved changes in your PDF document, as you will need to restart the application for the reset preferences to take effect.
Reset All Warnings in Preferences
Resetting the hidden warning messages in the application's general settings will bring back the 600 DPI conversion dialog.
When you select 'Do not show this again' on certain prompts, the application hides them globally in your user profile. The highlighting feature itself is not broken; the software is simply skipping the required resolution conversion step. Resetting your warnings will restore this functionality.
Launch Adobe Acrobat. Click on 'Edit' in the top menu bar and select 'Preferences' from the dropdown menu (or press Ctrl+K).
In the left pane of the Preferences dialog box, click on the 'General' category.
Locate the 'Warnings' section on the right side and click the button labeled 'Reset All Warnings'.
Click 'OK' at the bottom to save your changes, then completely close and restart Adobe Acrobat.
Open your scanned PDF and try highlighting the text. When the 600 DPI conversion warning appears, allow the conversion and proceed with highlighting.
Easily Highlight Scanned PDFs with WPS Office
Bypass complex resolution warnings and hidden dialogs by using WPS Office. With its powerful built-in OCR (Optical Character Recognition) technology, WPS PDF effortlessly converts scanned images into selectable, highlightable text in just a few clicks.
- 1. Open Your Scanned PDF: Launch WPS Office and open the scanned PDF document you want to highlight.
- 2. Use the OCR Tool: Navigate to the 'Tools' tab on the top ribbon and select 'OCR'. Choose to extract or convert the image to selectable text.
- 3. Select the Highlight Feature: Once the text is recognized, click on the 'Comment' tab and select the 'Highlight' tool.
- 4. Highlight the Text: Click and drag your cursor over the text to apply the highlight color smoothly.
Frequently Asked Questions
Why does a scanned PDF need to be 600 DPI for highlighting?
Scanned PDFs are essentially flat images. A higher resolution, such as 600 DPI, provides enough clarity for Optical Character Recognition (OCR) engines to accurately identify the letters, allowing the software to snap the highlight tool specifically to the text rather than acting as a freehand drawing tool.
Can I highlight a scanned PDF without converting its resolution?
Without OCR or proper resolution conversion, you cannot select actual text. However, you can use freehand annotation tools like a marker or area highlight tool to draw over the document manually.
What should I do if the 'Reset All Warnings' button is missing or grayed out?
If the button is inactive, it means there are no suppressed warnings stored in your current user profile. If you still cannot highlight text, the PDF might be secured against editing, or you may need to manually run an OCR scan on the document.
