Try running the commands below in a new terminal window.  You can run the bash shell and set the environment variable FS_LICENSE to point to the license.txt file you downloaded after filling out the form, MailScanner has detected a possible fraud attempt from "secure-web.cisco.com" claiming to be https://surfer.nmr.mgh.harvard.edu/registration.html   I used an Intel Mac below, but it should work if you are on a newer Mac with the M1 or M2 chip.

- R.

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iMac:~$ source /Applications/freesurfer/7.3.2/SetUpFreeSurfer.sh
-------- freesurfer-darwin-macOS-7.3.2-20220804-6354275 --------
Setting up environment for FreeSurfer/FS-FAST (and FSL)
FREESURFER_HOME   /Applications/freesurfer/7.3.2
FSFAST_HOME       /Applications/freesurfer/7.3.2/fsfast
FSF_OUTPUT_FORMAT nii.gz
SUBJECTS_DIR      /Applications/freesurfer/7.3.2/subjects
MNI_DIR           /Applications/freesurfer/7.3.2/mni

iMac:~$ pwd
/Users/myuserid
iMac:~$ echo $HOME
/Users/myuserid
iMac:~$ ls license.txt
license.txt
iMac:~$ export FS_LICENSE=$HOME/license.txt

iMac:~$ which freeview
/Applications/freesurfer/7.3.2/bin/freeview

iMac:~$ freeview   <-- SHOULD OPEN AN EMPTY FREEVIEW WINDOW

iMac:~$ freeview $SUBJECTS_DIR/bert/mri/brain.mgz   <-- SHOULD DISPLAY KNOWN TO BE GOOD VOLUME FILE