In a View, does the order of pages/blocks/attachments matter? & Why isn't my block showing up? Views 7x3x:
I have two pages &amp; a block in my view in this order:

[Page1] [Page2] [Block1]

Page1: path/%
Page2: path%/%
Block1: (no path)

I have the same contextual filter on all three, Page2 has a second contextual filter. My block is not appearing as expected. I have the block in the proper region without any restrictions in the block configuration.

In the contextual filter for the block, I've set it to hide the view if the value isn't present in the url. In the view preview, arguments produce results as expected. However in the live view, nothing shows up. (I'm providing the same filter arguments in the url)

When I change the contextual filter to display all results when filter value is NOT available, everything works as expected, but this isn't the behavior I want.

What else could be hiding my block/view?
Does the lack of a path for my block mean it can't see the argument?
You likely arent providing the argument to the view in any fashion it can use it. Try not hiding the view but echoing the args to the view title or header and see what you are getting. Please consider using panels module or providing default arguments to your view instead. This works if the arguments are simple like node/user/term id. 

If you post more specifics about your actual conditions i can help.