# Catching MachineUnderflow in Version 11.3

Ilian's answer to question 72229, involves

SetSystemOptions["CatchMachineUnderflow" -> False]


Evidently, this worked in earlier versions of Mathematica, but in version "11.3.0 for Microsoft Windows (64-bit) (March 7, 2018)", it does not, returning

SetSystemOptions::sysname: CatchMachineUnderflow is not a known SystemOption.

Does an alternative exist in the new version of Mathematica?

• Does SetSystemOptions["CheckMachineUnderflow" -> False] work for you? – Henrik Schumacher Jun 2 '18 at 18:48
• No, this is a different option that controls whether a machine underflow warning is issued in some circumstances. But there is no way to automatically switch to arbitrary precision as in earlier versions. – ilian Jun 2 '18 at 19:25
• @ilian Thanks for the info. I wonder what the reason behind this design decision was... – Henrik Schumacher Jun 2 '18 at 20:26
• @bbgodfrey Thanks for telling me =D – Henrik Schumacher Jun 2 '18 at 20:26
• @bbgodfrey Alternative in what sense? This command is simply not needed in 11.3 and later because what it accomplishes is now the default (and only) behavior, so you can think of "CatchMachineUnderflow" as being permanently set to False. There are also some new warning messages that can be easily turned off. – ilian Jun 2 '18 at 23:08

This command is simply not needed in 11.3 and later because what it accomplishes is now the default (and only) behavior, so you can think of CatchMachineUnderflow as being permanently set to False. There are also some new warning messages that can be easily turned off.
In version 12.0, we should set SetSystemOptions["CheckMachineUnderflow"->False]. In this way, we can turn off the prompt message.