In the search window, this seems to work for me: [Catalog #]="" (meaning no Catalog #).
Ah, right. I'm sorry. I did not take your meaning in your earlier reply. When you say 'search window', you mean the top right search box in the Media Center interface.
Okay, so, when I search as you suggest in the search window with [Catalog #]=8.553630, I do get the correct search result expected. However, the same search done using MCWS, as in:
http://localhost:52199/MCWS/v1/Files/Search?Action=JSON&ActiveFile=-1&Zone=-1&ZoneType=ID&Query=([Catalog%20#]=8.553630)
or
http://localhost:52199/MCWS/v1/Files/Search?Action=JSON&ActiveFile=-1&Zone=-1&ZoneType=ID&Query=([Catalog%20#]=[8.553630])
produces only a list of files containing "catalog" in the Name or Filename fields, and definitely not the same search results I got from the Media Center interface.
So, MCWS is not correctly interpreting the search criteria, or at least, not in the same manner as the front-end search interface in Media Center.
I hope that makes sense.
Thank you.