The cause appears to be the use of non-ASCII characters in file names. Microsoft describes it like so: “Any user may be ...

Every email provider comes with some limitations, and almost all of them have one thing in common – limited attachment size. It doesn’t matter whether you use Gmail or Outlook as your email management ...

As spotted by Bleeping Computer, Microsoft has published a new service alert related to Outlook. Labelled as issue EX1189359 and titled "Users may be unable to open Excel files attached to email ...