I’ve had several people report that the nvALT Tag Search workflow for Alfred 2 hasn’t been working for them. I just updated the download with version 1.1. It removes some of the criteria for the file filter and hopefully generalizes the search enough to work for more people.
Please be sure to open the workflow and double-click the File Filter input in the workflow. Under Search Scope you need to make sure it points to the folder where you store your text files. Related: you have to have your database stored as text files.
Hope this helps, it’s a really handy tool when it works.
Update: I just uploaded version 1.2, which fixes the “.ext” appearing in non-“md” file searches. It should work with any extension now.