You didn't mention what version you are running or whether you have any third party add ons or customizations.

I have not heard of random back orders. In any event, a possible solutions (assuming that you do not want to allow any backorders) would be as follows:

1. Make sure that in role maintenance | Tab 2 security events | Sales Order that the box for allowed to backorder all items is cleared.
and
2. Make sure that all items have the option for "allow backorders" cleared (IM | Item Maintenance | Tab 2 Additional). A fast way to apply this to all items is to use Product Line Maintenance. Select a product line and make sure that allow back orders is not checked. Click the apply button. Select the check back for allow back orders (this means you are applying the value), select your item code range (or ALL in this product line) and click proceed.

You didn't mention what version you are running or whether you have any third party add ons or customizations.

I have not heard of random back orders. In any event, a possible solutions (assuming that you do not want to allow any backorders) would be as follows:

1. Make sure that in role maintenance | Tab 2 security events | Sales Order that the box for allowed to backorder all items is cleared.
and
2. Make sure that all items have the option for "allow backorders" cleared (IM | Item Maintenance | Tab 2 Additional). A fast way to apply this to all items is to use Product Line Maintenance. Select a product line and make sure that allow back orders is not checked. Click the apply button. Select the check back for allow back orders (this means you are applying the value), select your item code range (or ALL in this product line) and click proceed.

My apologies, here is the info.

Sage 100 Advanced 2016 (Version 5.30.2.0) - no 3rd party add-ons, customization limited to User Defined Fields, Screens and Custom Forms
Windows 10 Professional (x64)
Windows Server 2012 R2 Standard
SQL Server 2014

Nothing there that would change my thoughts.

Do note that the backorder field will be present on your sales order screen by default. It may not be in the primary windows but it should be in the secondary window (unless you have hidden it). So there is always the possibility that someone may be accidentally changing it without realizing it.

If you don't allow backorders at all, my previous suggestions SHOULD work unless there is something else going on.

We do allow backorders, so your solution might not work for us. I'm looking into that. There seems to be something else going on, not a data entry error as one would suspect.

The strange thing is the system appears to be pulling in the unit price into the backorder qty field.

Sorry, thought you said that you don't do back orders.

On my system by default, the primary window on the lines tab has Item Code, Ordered, Back Ordered, Unit Price, Extension , Comment.

I could see where it might be easy to be in a hurry and put in an ordered quantity immediately followed by the unit price (in the back ordered by mistake). I note that if you do this the back ordered quantity cannot be higher than the ordered quantity.

Any possibility that the person having the trouble has this same configuration as mine (different users can have different configurations)? If so have them drag the back ordered field into the secondary data entry grid.