This is a recent feature added to FreeSurfer to make it easier for tools like FMRIPREP which bundle FreeSurfer in to ask users to use their own license. (Up until now, we’ve been using one of our own license.)
FreeSurfer licenses are free, but they use registrations to keep rough statistics on the number of users, which they can use in grants and presentations as a demonstration of their contribution to the neuroimaging community. You can register here: https://surfer.nmr.mgh.harvard.edu/registration.html
Once you have a license, there are two ways to let FMRIPREP know about it:
- Set the
FS_LICENSEenvironment variable with the path of the file, in e.g., your.bashrc - Pass the
--fs-license-file <PATH>option to FMRIPREP, where<PATH>is the location of your license file