Square symbols don't always convert to check boxes
I'm using Adobe Acrobat XI. I used to use Adobe Acrobat X, and encountered the same problem.
I create some REALLY lengthy forms in Word. I apply a style with square bullets to text in Word to create a checkbox list. Then I convert the file to PDF, and then convert the PDF to a form. Every line has the same Word style with the same square symbol for its bullet, so there's nothing about the way I'm applying the formatting that's inconsistent.
I've learned from trial and error that square bullets only convert to checkboxes if the font is 10pt or larger. I've also learned that you have to apply a specific square symbol (I'm sorry - I don't have the ASCII code for it), or it won't work. I've tested numerous square symbols (Insert+Symbol in Word), and keep returning to my go-to square. This square even works when you insert it in the middle of a line.
Naturally, I never seem to encounter problems in one-page forms. But when I'm creating forms with hundreds or thousands of items on a checkbox list, only SOME of these square boxes convert to check boxes. I don't know why. Then I have to manually copy/paste the checkbox fields, move them into position, and give each one a unique name. It's crazy-making unnecessary work.
The font I use is Calibri because it's compact. I have to keep pages to a minimum, and larger, more spread-out fonts like Verdana create too many extra pages.
•I've tried breaking up the document into pages and converting each one separately, and most of the same checkboxes still don't convert in these smaller files.
•I've tried creating a new document and recreating the styles, then copy/pasting the content into the new file (I can't type it line-by-line to recreate it from scratch - the affected forms are far too long).
•I've tried increasing the font size to 11pt, but if it doesn't convert at 10pt, it won't convert at 11pt.
•I've changed the font, and checkboxes still don't convert.
•When I still had access to Adobe X, I tested converting the file in BOTH versions. There was some difference in which checkboxes didn't convert, but the problem was there too.
Please see the attached image.
The form field detection algorithm is not perfect, and only provides a good starting point.
You will require manual work to create fields that are not detected by Acrobat
As a workaround, you could try inserting “Square shape” instead of bullets.
Click Insert, click Shapes, select a shape, and then click and drag to draw the shape.
I hope this work for you.