Laravel 5.3 storage:link -> symlink(): Protocol error

Your problem probably is that you have to start your vagrant box as a system administrator.

So hit start type "cmd", right click it choose "Run as administrator". Navigate to your project, type "vagrant up". Retry the command.

Creating symbolic link on Homestead?

First close vagrant with vagrant halt command, then run cmd as administrator, go to your homestead folder, start Vagrant with vagrant up and then you can run php artisan storage:link. For me it worked :)

Run cmd as Super Admin.

php artisan storage:link is OK.