Anyone has solved a similar problem with 'Invalid FreeSurfer license key'? 

I have just got a license though email, and put the four-line code in a file named license.txt. Now the file is in the folder where I installed freesurfer. It should work well but it didn't. 

When I used tksurfer, something was printed out. "ERROR: Invalid FreeSurfer license key found in license file xxxxx/freesurfer/license.txt" 

Please help. 

Thanks,

Xiangzhen