Results files are generated by default in XML and HTML format (dataLoaderresults.xml and dataLoaderresults.html). If you're running batch operations, the dataloader will overwrite these results files.
Data Loader lets you specify a unique name (that won't be overwritten for each operation).
To name the XML-formatted file, use the -rx option.
To name the HTML-formatted file, use the -rh option.
The results file shows the total number of items that succeeded and failed, as shown below:
<MetaInfo Time="3/24/2006 2:38:01 PM" Successes="2" Failed="0" />
The file also includes detailed information for each failed item, for example:
<NotFound Message="The Retention Rule with name 0-Archived was not found.">
Or
<DataMalformed Message="The date '4/5/04' was not in the correct format. The correct format is yyyy'-'MM'-'dd HH':'mm':'ss'Z'.">