-AutoAdjustMacroMappingRange will make it so that when you map a parameter to a macro control, the current value becomes the minimum value of the newly-created mapping (rather than 0).
I prefer enabling this option because it streamlines workflow by helping to map macros faster, saving the step of typing in the minimum value when it is already in place.

With -AutoAdjustMacroMappingRange off, when mapping a parameter to a macro control, it will always result in a range of “min” to “max”, ragardless of the current position.

Say i want to map a parameter to a macro, and i want it to range specifically from 37 to 127.

With -AutoAdjustMacroMappingRange set to off, i would first have to map the parameter, click “map”, and then edit the minimum value to be 37.

However, with -AutoAdjustMacroMappingRange set to on instead, by mapping it, the minimum value will automatically be set to the current value (in this case 37), while the maximum will default to 127.

For cases where the maximum is meant to be 127, this reduces the mapping process to a single quick step, without even needing to open map mode. Other types of mappings might still require turning on map mode to adjust the values, but will still save a step of action if you map it while the current value matches one of the target values.

The unprocessed screengrab below demonstrates various mapping strategies, depending on what you want the minimums and maximums to be.

. . .

NOTE: i believe that a recent update of Live 10 enables AutoAdjustMacroMappingRange by default, whereas in previous versions it was off unless you enabled it manually. Either way, it’s handy to know that you can change it around when desired. Just remember that if you do change it, you’ll have to restart live for the change to take effect (i think).

“How the heck do i implement this?” you might ask. To answer that and for more swag info about Ableton Live’s mysterious Options.txt, Madeleine Bloom’s series on the topic is highly recommended.