https://help.tallysolutions.com/docs/te9rel65/Voucher_Entry/Accounting_Vouchers/Warn_on_Negative_Cash_Balance.htm

Warn on Negative Cash Balance

You can configure Tally.ERP 9 to prompt you with a warning when the Cash ledger reaches a negative balance.

Go to Gateway of Tally > Accounting Vouchers.

Set the option Warn on negative cash balance to Yes in F12: Configure screen .

Accept the screen to save.

For example, let us assume there is a cash balance of Rs.25000 and you need to make a payment of Rs.26000 towards Advertising expenses. This results in a negative cash balance. The Payment entry is displayed as shown:

Tally.ERP 9 prompts you with a negative cash warning message and the credit cash balance in RED Colour. This will help you to decide whether to proceed with the entry or not.