I have hit an issue where messages are simply not showing. The code snippet below should demonstrate the problem...

Declare our message

In[1]:= foo::fooMessage = "Hello World";

Declare our function

In[2]:= foo[n_] := Message[foo::fooMessage]

Execute our function; Note that there was no output (Message output was expected)

In[3]:= foo[1]

Show our message to make sure it was all defined correctly etc

In[4]:= foo::fooMessage


Out[4]= "Hello World"

Double check that our message was actually assigned to our function as expected

In[5]:= Messages[foo]

Out[5]= {HoldPattern[foo::fooMessage] :> "Hello World"}

For some reason the Message function does not appear to be generating any output. I have tried several examples from other sources and they also appear to have the same issue. I am using Mathematica 10.0.1 on OSX Yosemite.

Thanks for any input.