If you still get a PLOT.LOG file after you unselected it in the Options / Plot tab, note you need to check the Plot dialog box. This plot log file creates a log file of the plot stamp each time you plot in AutoCAD. This file can be created even if plot stamp is unchecked in the Plot dialog box.
To access the plot stamp log file check box, open the Plot dialog box (type Plot at the command prompt or choose Plot from the Ribbon) and select the box “Plot stamp on.” Click on the plot stamp icon that appears. In the Plot Stamp dialog box choose “Advanced” and uncheck “Create a log file” in the Advanced Options dialog box. Click OK, OK, and Cancel to get out of the Plot dialog boxes.
Notes from Cadalyst tip review R.K. McSwain: The setting is buried in several nested dialog boxes. If you don't want any PLOT.LOG files to be created, this is the tip for you. Thanks, Nancy!