If you have a .pdf document that has previous been saved with highlighting and now you want to remove the highlighting and save it, you may find it won’t save. You reopen it and the highlighting is there again. I’ve found a work-around. Click on the highlighted field and click delete on your keyboard to unhighlight the selection Do this for each selection you want to unhighlight. Now, under the “Forms” menu, choose “Edit Form in Designer”. You may get a pop-up, click OK. Once the form is open in edit mode, click the “File” menu and choose “Save As”. Save it on your computer someplace. You may get another pop-up that says something about “Do you want Adobe Acrobat to distribute this form….”. Just click No. Now, when you open your form, the highlighting should be gone.
Let me know if this works for you!