Attached is screen shots for the expected necessary files for each appraisal district.  If a file is missing from a supplement that is not in the screen shot the supplement may not load. 

For Harris County normal monthly supplements,

The AD Importer is intended to load all monthly supplements for all years at the same time.  Go to the HCAD website and download the supplement do not unzip them as the AD Importer knows what to look for.