# -*- coding: utf-8 -*-
''' Поиск e-mail в файлах'''
import re, os
dir = r'C:\email'
email = "info@example.com"
directory = os.listdir(dir)
for files in directory:
    fullname = os.path.join(dir, files)  
    if os.path.isfile(fullname):
        with open(fullname, encoding='utf-8', errors='ignore') as file_in_db:
            read_file = file_in_db.read()
            search = re.findall(email, read_file)
            strings = '\n'.join(search)
            if len(search) > 0:
                print (fullname)
                print("E-mail %s найден" % email)
                print (strings)
    else:
        print ("E-mail не найден")

Traceback (most recent call last):
  File "C:\search_email.py", line 14, in <module>
    read_file = file_in_db.read()
MemoryError

with open(fullname, encoding='utf-8', errors='ignore') as file_in_db:
            read_file = file_in_db.read()

with open(fullname, encoding='utf-8', errors='ignore') as file_in_db:
            for sting in file_in_db:
                search = re.findall(email, string)
                strings = '\n'.join(search)
                if len(search) > 0:
                    print (fullname)
                    print("E-mail %s найден" % email)
                    print (strings)