Settings marked with an asterisk [*] are remembered between program invocations.
Marching Waveforms: Check to enable simulation results to be incrementally plotted during the simulation.
Generate Expanded Listing: Dump the flat netlist after expanding subcircuits to the in the SPICE Error Log file.
Open Demo circuits as regular schematics: Use [File] [Open] to open demo circuits in .\LTspiceIV\lib\app\*.app. All SPICE commands will be visible. The schematic can be edited and saved to a new file. The double dots '..' is for demo circuit display control use. Only one dot is required for editing.
Don't warn when using preliminary models: Turn off the warning message for all preliminary models. Note: All SMPS models are flagged as preliminary as a disclaimer.
Automatically delete .raw files: This allows waveform data files to be deleted automatically after closing a simulation. This dramatically reduces the amount of disk space used by LTspice but requires the simulation to be rerun when you reopen the simulation.
Automatically delete .net files: This allows the schematic's netlist to be automatically deleted whenever the schematic is closed. These files can be thought of as small temporary files and deleting them makes exploring the directory tidier. They define the electrical connectivity of the schematic to the LTspice simulator. Some people prefer not to delete them because they have further use for them.
Automatically delete .log files: This allows the simulation log to be automatically deleted whenever the simulation is closed. These files contain various simulation statistics such as elapsed time during the simulation, warning and error messages, and step parameters used for .step/.temp/.dc analyses.
Directory for Temporary Files: Directory for temporary storage of waveform and update files.