To help troubleshoot the issue, I'd like you to do the following:
1. Start the software.
2. Click on "Options".
3. Click on the "Troubleshooting" tab.
4. Check the "Enable logging for support purposes" checkbox.
5. Click "Save", then exit and restart the software.
6. Try to convert the file(s) that are causing the problems.
7. Go back to the "Advanced" tab.
8. Click the folder icon near the bottom left.
9. Then zip (select all folders, right-click, click "Send To", then click "Compressed (zipped) folder") and attach the logs in a support request at http://www.muvenum.com/support
, so we can take a look at the information provided.