• Definitely have a look at the python logging page and the logging cookbook for some simple patterns on building a logger.

• Other thoughts are: class Log() doesn't do what it says it is. It alerts, and passes a "download completed" message to the logger. I'd recommend separating the functionality there and renaming the class to what it actually does.

• Move the code from Start() into the __main__ - you're not making it a class so there's no point on having that code separate.

• For this (spelling error btw):

   if not self.location:
       self.loaction = os.getcwd()
  

you might want to just call self.GetSaveDir() as that's doing the prompting to get the value of the location to save, correct?

• D.R.Y. here (also saving a log message to say "refer to the log is kind of redundant, right?):

   except Exception as err:
       AddLog(err)
       Log.error("Exception, please refer to log")
  

• With:

   urlYT = self.getUrlE.get()
   if urlYT == "":
       Log.error("Please enter a url")
       return
  

Perhaps you could make this a loop (or check for 'exit' to abort) on the response. Something like (untested):

    while not (urlYT = self.getUrlE.get())
        Alerter.error("Please enter a URL or use 'exit' to abort.")
    if "exit" == urlYT:
        return

• The function def CreateUI(self, master): is huge. You should be aiming for as few lines as possible in a function. I'd suggest refactoring each operation inside that function into their own separate functions so def CreateUI(self, master): becomes smaller. For example:

   def CreateUI(self, master):
       build_urls()
       build_file_format_getter()
       set_form_formats()
       set_location_buttons()
       set_logger()
       set_progress_bar()
       set_download_button()
  

The reason is, if you have a bug, you're not searching 50 lines for the cause. You only have to look at a specific function where the problem is.

• Finally, the naming of your variables aren't PEP8. Hope this can help :-)

• Definitely have a look at the python logging page and the logging cookbook for some simple patterns on building a logger.

• Other thoughts are: class Log() doesn't do what it says it is. It alerts, and passes a "download completed" message to the logger. I'd recommend separating the functionality there and renaming the class to what it actually does.

• Move the code from Start() into the __main__ - you're not making it a class so there's no point on having that code separate.

• For this (spelling error btw):

   if not self.location:
       self.loaction = os.getcwd()
  

you might want to just call self.GetSaveDir() as that's doing the prompting to get the value of the location to save, correct?

• D.R.Y. here (also saving a log message to say "refer to the log is kind of redundant, right?):

   except Exception as err:
       AddLog(err)
       Log.error("Exception, please refer to log")
  

• With:

   urlYT = self.getUrlE.get()
   if urlYT == "":
       Log.error("Please enter a url")
       return
  

Perhaps you could make this a loop (or check for 'exit' to abort) on the response. Something like (untested):

    while not (urlYT = self.getUrlE.get())
        Alerter.error("Please enter a URL or use 'exit' to abort.")
    if "exit" == urlYT:
        return

• The function def CreateUI(self, master): is huge. You should be aiming for as few lines as possible in a function. I'd suggest refactoring each operation inside that function into their own separate functions so def CreateUI(self, master): becomes smaller. For example:

   def CreateUI(self, master):
       build_urls()
       build_file_format_getter()
       set_form_formats()
       set_location_buttons()
       set_logger()
       set_progress_bar()
       set_download_button()
  

The reason is, if you have a bug, you're not searching 50 lines for the cause. You only have to look at a specific function where the problem is.

• Finally, the naming of your variables aren't in line with PEP8. Hope this can help :-)