Can't Highlight or Add Comments in Adobe Reader — How to Enable It
Greyed-out annotation tools in Adobe Reader mean the PDF either has restrictions set or lacks Reader Extended Rights. Here's how to enable highlighting and comments.
Opening a PDF in Adobe Reader and finding the Highlight, Sticky Note, and other annotation tools greyed out or unavailable is a permissions issue — not a Reader bug. Free Adobe Reader restricts annotations on PDFs that do not have "Reader Extended Privileges" enabled. Understanding which restriction applies points you to the right fix.
Why Annotation Tools Are Disabled
Adobe Reader has two tiers of functionality: the base Reader (free) and Reader with Extended Privileges. By default, Reader only allows annotating PDFs that were explicitly enabled for commenting by the document creator using Acrobat Pro. PDFs without Extended Privileges show the annotation tools as available but with a notice that annotations cannot be saved, or greyed out entirely. This was a business decision by Adobe to differentiate the free Reader from the paid Acrobat Pro — not a PDF standard limitation.
Fix 1: Use a Browser Instead of Reader
Chrome, Edge, and Firefox all allow highlighting and annotation in their built-in PDF viewers without any restrictions. Open the PDF in Chrome (File → Open or drag onto a tab), click the highlight tool in the top toolbar, and annotate freely. Chrome saves annotations to the file when you download. This is the fastest fix and works for the vast majority of PDFs. The browser viewer respects the same permission flags but applies them differently — Chrome allows highlighting regardless of Reader Extended Privileges.
Fix 2: Enable Reader Extended Privileges (Document Authors)
If you own the PDF and want recipients to annotate it in Adobe Reader: open the PDF in Acrobat Pro → File → Save As Other → Reader Extended PDF → Enable Commenting & Measuring. This adds a usage rights signature to the PDF that unlocks Reader's annotation tools for all recipients. Only one person (the document author with Acrobat Pro) needs to do this once — all recipients with free Reader can then annotate the enabled PDF.
Fix 3: Remove Permission Restrictions
If the PDF has explicit "No Annotations" permission set via an owner password: remove the restriction using FixMyPDF Unlock. Owner-password restrictions (which govern permissions like annotating, copying, and printing) can be removed without knowing the owner password. Once restrictions are removed, all PDF viewers including Reader will allow full annotation. Note: this only works for owner-password restrictions, not user-password encrypted PDFs (where you need the actual password).
Fix 4: Use a PDF Editor Instead
For PDFs where you cannot remove restrictions and do not have Acrobat Pro: use a third-party PDF editor that does not enforce Reader-style restrictions. PDF-XChange Editor (free tier), Foxit PDF Reader, and FixMyPDF's editor all allow annotation regardless of Reader Extended Privilege status. These tools implement their own annotation capabilities rather than relying on Adobe's Reader privileges system.
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