Why Lifecycle Designer ES4 crashing on a pdf form created in ES2

Question

On HP Probook 4730s laptop with Windows 7, Designer ES4 keeps crashing on a pdf form created in ES2. Opening it in Adobe Acrobat Pro XI and reader is fine. Installed the ES4 sp1 did not help. Other forms are fine. No special fields on the form except some basic textboxes, signatures, checkboxes, lines.
Any idea about how to fix this?
Thanks

Answer 1

Using PDFStreamDumper, I found this:
<form checksum="/I/bugqsY9MYw688CDeeueRfqaM=" xmlns="http://www.xfa.org/schema/xfa-form/2.8/"
><subform name="form1"
><instanceManager name="_"
/><subform
><field name="Button1" presence="hidden"
/></subform
><instanceManager name="_"
/><subform
/><instanceManager name="_"
/><subform
/><instanceManager name="_"
/><subform
/><field name="SignatureField1"
/><field name="SignatureField1"
/><field name="SignatureField1"
/><field name="SignatureField1"
/><field name="SignatureField1"
/><field name="SignatureField1"
/><field name="SignatureField1"
/><field name="SignatureField1"
/><field name="SignatureField1" access="readOnly"
/><pageSet
><pageArea
/><pageArea
/><pageArea
/><pageArea
/></pageSet
></subform
></form
>
Note the same signature field has been defined multiple times. I'm not sure how this happened, but seems like a likely culprit. In the future, try to keep your forms as XDPs until you need to distribute them, then save them as PDFs. The XDP files are just text, and thus easier to fix if something goes wrong.