python: why does os.makedirs cause WindowsError?

In python, I have made a function to make a directory if does not already exist.

def make_directory_if_not_exists(path):
    try:
        os.makedirs(path)
        break    
    except OSError as exception:
        if exception.errno != errno.EEXIST:
            raise

On Windows, sometimes I will get the following exception:

WindowsError: [Error 5] Access is denied: 'C:\\...\\my_path'

It seems to happen when the directory is open in the Windows File Browser, but I can't reliably reproduce it. So instead I just made the following workaround.

def make_directory_if_not_exists(path):
    while not os.path.isdir(path):
        try:
            os.makedirs(path)
            break    
        except OSError as exception:
            if exception.errno != errno.EEXIST:
                raise
        except WindowsError:
            print "got WindowsError"
            pass       

What's going on here, i.e. when does Windows mkdir give such an access error? Is there a better solution?