Assuming you tried sudo, you may want to check if there are any other processes that are using the /usr/local/bin directory. You can use the lsof command to list all the open files and processes that are using the directory.
Reset my Mac and seemed to work until I try begin coding.
After dfx start I get the following error :
Using the default definition for the 'local' shared network because /Users/*******/.config/dfx/networks.json does not exist.
Dashboard: http://localhost:50245/_/dashboard