Problem

We have several users who look after sales and purchasing who are in different offices.
Often, one user will input e.g. a sale; however, other users cannot see this sale immediately which can result in the sale being input again by another user.

A bit more detail

I am unaware of what triggers this: it may be that User B has the sales orders records open when User A inputs the sale. I am not sure.

Sometimes User B may be aware that User A has input a sales record, but cannot see it.
Sometimes the record will appear if the records are sorted in a different way then resorted (e.g. by Name, then back to No.). Sometimes this doesn't work.
Sometimes User B will have to open up a different record list (such as Purchase Orders), then go back to e.g. the Sales List (this works even less often).
In some cases, User B may resort to closing Sage and re-opening in order to see the record.

Resulting Issues

• Sales can be input twice
• Purchase orders can be input twice (which is more of a problem as it requires cancelling an order with a supplier)
• Customers can be given 'incorrect' or conflicting sales order references
• Communications and paperwork would have 2 different sales order references; which are difficult to tie together effectively once discovered.
• Manual invoices and could be input twice

Question

Does anyone know of any way to stop this from happening?

Closing down the program and reopening everytime you want to input a new job is not convenient
Double checking verbally with all other users before entering a job is not always possible and is also inefficient.