Can you please share an example dataset so I can try to reproduce and fix this error?
- Right-click on the subject folder > File > Duplicate subject
- In the duplicated subject, delete all the files that are not necessary to reproduce the error. Keep the MRI, the selected surfaces (in green), the channel file, one trial and the associated source file that causes this error
- Right-click on the duplicated subject > File > Export subject
- Upload the .zip file somewhere (dropbox, google drive...) and post the download link here
Thanks