Hello,
Do you have additional information about the issue? To be specific:
- Is the user getting an error? If so, please include it in your next reply.
- Does the form open for other users (on other machines)? If so, have you checked the machine build for any differences in the installed software?
- Which version of InfoPath does the user have installed? Do they have the latest updates?
These items should help you to begin troubleshooting the issue. Once you have more details, please post them here to get more ideas and feedback from the community. Good luck!