Are you certain that there is text to recognize?
Also, and someone else with more expertise than I can answer this, will NVDA OCR (which uses Windows 10 OCR) actually process an entire document or just the portion visible on the screen? The User Guide and Quick Commands Reference both state, "To recognize the text in the current navigator object using Windows 10 OCR, press NVDA+r." I have never been entirely clear as to what the scope of "the current navigator object" is in this context.
Brian - Windows 10 Pro, 64-Bit, Version 20H2, Build 19042
Always remember others may hate you but those who hate you don't win unless you hate them. And then you destroy yourself.
~ Richard M. Nixon