You can narrow down which suppliers may be dormant by following these steps:
Go to Purchase Ledger
Select Suppliers
Click on Check Dormant Suppliers
You can then enter the criteria that is on screen and click 'Next' to bring up a list of suppliers that meet the criteria you selected. ( For example, suppliers with no transactions in the past year. If no date is selected, the suppliers not used for 6 months or up will be displayed ).
In the next screen, a list of eligible suppliers will be displayed, where you can then select and mark Suppliers as dormant by selecting the tick box next to applicable Suppliers and selecting the action 'Set To Dormant' in the action bar drop-down menu, then clicking the 'Apply Action' arrow.
This will mark the selected suppliers as dormant in the system.