Moving model database
Follow below steps :

    a. start SQL Server in master-only recovery mode

     for Default instance : NET START MSSQLSERVER /f /T3608

     for Nameed Instance  : NET START MSSQL$instancename /f /T3608

    b. Check the file location 

          SELECT name, physical_name AS CurrentLocation, state_desc
            FROM sys.master_files
            WHERE database_id = DB_ID(N'model');

    4. sp_detach_db 'model'
        go

    3. Move the Model.mdf and Modellog.ldf files from OLD_LOCATION to NEW_LOCATION
    4. Reattach the model database as follows:
    use master
    go
    sp_attach_db 'model','G:\model\model.mdf','G:\model\modellog.ldf'
    go
   5. Stop SQL Server : NET STOP MSSQLSERVER or NET STOP MSSQL$instancename
   6. Restart SQL Server Normally : NET START MSSQLSERVER or NET START MSSQL$instancename
   7. Verify the new location : sp_helpdb model