I'm trying to add text to a pdf in edit mode in Adobe Acrobat DC Pro. This seems to work until I get to page six, when I get the popup "Adobe Acrobat has encountered an unknown error" and I'm no longer able to edit my document.
How can I resolve this issue? Has anyone else had this problem? The whole point of purchase was to combine files into a pdf and be able to edit them.
Things like this often are caused by a corrupt PDF file. What types of edit operations are you performing?
One thing I would try is to do a "File>Save As" before performing any edits. Does this result in an error message? If so, and if there is a numeric error code on the error dialog, hold down the Ctrl key when you click on the "OK" button on the error dialog. What does the second popup say? If you don't get an error, try to edit this newly saved document. Does it also cause a problem on page 6?
What happens when you try to extract just page 6 and save it in a new file? Can you then edit this page in the new file?