I'd like to share my solution for this as it was driving me insane for the period I could not resolve this for a user.

Symptoms

• On opening any Incopy file in CC, exporting the file to PDF would cause a software crash
• The PDF itself would still be exported despite Incopy crashing
• Event viewer did not show anything outstanding as the main culprit for the crashes
• Exporting to PDF in CS6 was fine, while exporting in CS7 was also fine.

Solution

• Close any instances of InCopy you have running
• Head to the AppData folder for Incopy in the directory<username>\AppData\local\adobe\InCopy and rename 'InCopy' to InCopy.old
• Head to the AppData folder for Incopy in the directory<username>\AppData\roaming\adobe\InCopy and rename 'InCopy' to InCopy.old
• Restart the machine and attempt to export to PDF once more.

Again this is what worked for me and it may not work for anyone. But I thought to make some documentation as I could not find this anywhere on the web when doing my investigation. Hopefully people in future will find this on Googleling.