You might receive a warning message when you execute a SAS Data Integration Studio job that contains a User Written Code, File Reader, File Writer, Hadoop File Reader, or Hadoop File Writer transformation. The warning message can be similar to the following:

The reason the warning appears is because of a feature that was added to SAS Data Integration Studio in SAS^® 9.4 (TS1M3). When the source or target of a transformation is an external file, the file name is added to the macro variables _INPUT or _OUTPUT.  You receive the warning when the file name contains a macro variable, which is initialized in the body of any user-written code for the transformation.  The warning is issued when the macro variable in the file name of the _INPUT or _OUTPUT value is executed prior to the initialization of the macro.

Beginning with SAS^® 9.4 (TS1M6), a new option, Generate macro variables for external files, is available for the transformations in order to allow external files as source and targets. You should change the option setting to No to avoid the warning. The No setting indicates that the macro variable definitions for _INPUT and _OUTPUT should not be generated. The default setting for the option is Yes. 

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