The lock limit is set on the Matter Maintenance, this limit takes into account all the debt on the file unpaid bills +unbilled disbursements and unbilled WIP/Time.
This can be added by following the below steps:
From the Accounts Desktop go to the Admin tab.
Select Matter Maintenance.
Put in the Account Reference and select OK.
Select the Limits tab.
Put in the limit you require for all your debt.
Click on Apply and OK.
There are other limits that can be used that are in the same location:
Fees Estimate- This is Fees that are billed.
Time Limit- This is time only
Disbursement Limit- This is disbursements only
Total Charge Limit