Comment 2 for bug 1410640

The error in the logs is:

Traceback (most recent call last):
  File "/usr/lib/update-notifier/package-data-downloader", line 51, in create_or_update_stampfile
    with open(file, 'w'):
IOError: [Errno 2] No such file or directory: '/var/lib/update-notifier/package-data-downloads/ttf-mscorefonts-installer'
Traceback (most recent call last):
  File "/usr/lib/update-notifier/package-data-downloader", line 256, in process_download_requests
    create_or_update_stampfile(stampfile)
  File "/usr/lib/update-notifier/package-data-downloader", line 57, in create_or_update_stampfile
    os.utime(file, None)
OSError: [Errno 2] No such file or directory: '/var/lib/update-notifier/package-data-downloads/ttf-mscorefonts-installer'

The /var/lib/update-notifier/package-data-downloads/ directory is part of the update-notifier-common package. If it is missing from your system, you have a corrupted install. You will need to reinstall the update-notifier-common package to recreate it, or recreate the directory by hand with 'mkdir'.