Adobe acrobat pro에서 You are viewing this document in PDF/A mode라고 떠서 수정 안될때

검색하면 잘 나온다...

셋팅 바꿔라

http://superuser.com/questions/441404/how-to-convert-pdf-a-to-normal-pdf

You don't tell us, but I assume it: you are using Adobe Acrobat in order to 'crop' your PDF/A? Which exact version is it?

Anyway, in the Edit > Preferences > Document settings, you can switch off a Display PDF/A in PDF/A-mode.

Once you've done that the blue horizontal band informing you about the PDF/A property of the file at the top of each page will disappear, and it will be possible to manipulate the file. (You may need to re-open the PDF).

Once manipulated (and saved), the PDF/A property will be lost anyway.

Viewing PDF/A files in PDF/A-mode prevents Acrobat from changing the file (since PDF/A is for *a*rchiving).