This happen when we add payment mode to POS profile.
Here is an example of what mine looks like (v11)
All columns in payment type must be filled in and check marks in “Default” column if this profile is the default one to apply to this user:
This error coming, when I select the default mode of payment
It will save without any error if I not select default payment mode.
I am just confusing whats going on here…
Next time you save it TAB over to the Amount column and enter 0.00 then save it. The POS Profile system used to automatically default the zero amount for you but it may be broken in recent updates. So enter the zero amount yourself before saving.