Configure the option "Warning if a formula contains errors" (File | Options)

Here you can configure if PlanMaker shows a warning message when it detects a formula with errors.

Supported on: At least Windows Vista
Registry HiveHKEY_LOCAL_MACHINE or HKEY_CURRENT_USER
Registry PathSOFTWARE\Policies\SoftMaker\PlanMaker 2018
Value NameFormulaNotify
Value TypeREG_DWORD
Enabled Value1
Disabled Value0

softmaker.admx

Administrative Templates (Computers)

Administrative Templates (Users)