You drag to highlight a paragraph. Nothing highlights. You try double-clicking a word. The whole page selects as one block, or nothing selects at all.
The text you're looking at isn't text. It's a picture of text.
What's actually going wrong
PDFs can store text as vector characters or as images of text. Vector text is selectable, searchable, copyable. Image text is just pixels — your viewer can show it but can't interact with it as language.
Scanned PDFs are images by default. Some exports produce image-only output. And some PDFs deliberately rasterise text to prevent copying. The cure for all of them is the same: add a real text layer with OCR.
The quick fix
Run the PDF through convert PDF to Word. Flint's OCR reads the text from the image and generates a true text layer. Open the Word document — you can confirm the recognition looks right — then convert back to PDF.
The new PDF looks identical but text is fully selectable. Highlight, copy, paste, search — everything works.
If that didn't work
OCR quality depends on source legibility. Sharp scans recognise nearly perfectly. Faded or low-resolution scans produce more errors. For critical text, proofread the OCR output before relying on it.
If the PDF is intentionally locked against selection (some publishers do this), OCR still works — it reads the visual output, ignoring whatever restrictions the file claims. The selectability you create is yours, not the original's.
Prevent it next time
When scanning, enable OCR-on-capture in your scanner settings. When exporting from source, never choose 'rasterise text' unless you actively want to prevent editing. And for PDFs you'll work with repeatedly, OCR them once on receipt rather than every time.
FAQ
Why can I select text in some PDFs and not others?
PDFs with vector text layers allow selection. PDFs that are image-only don't. Most modern source-exported PDFs are selectable; most scans aren't unless OCR was applied.
Will OCR change how my PDF looks?
No. OCR adds an invisible text layer behind the existing image. The visible page looks identical. You just gain selection, search, and copy.
What if OCR gets some words wrong?
Open the Word file produced by Flint's OCR, correct the errors, then export back to PDF. The corrected text becomes the new selectable layer in your final PDF.
Can I copy text out of a protected PDF?
If the protection allows it, copy directly. If it doesn't, OCR via Flint reads the visual output and produces selectable text regardless of the original's restrictions.
If your highlight cursor does nothing, the PDF has no real text. Run it through Flint's OCR and selection works again.