Began QB 1 April, start of my FY. How do I treat expenses in March (last FY)? I want 1 April cash at bank to be right but don't want old expenses in new FY dashboard.

Great to see you here in the Community, @mn-solutions. 

Allow me to share some insights about treating the March expenses so these will not appear in the new FY dashboard. 

The Dashboard reports the expenses either by number of days or by calendar date. Removing the old expenses from the dashboard is currently unavailable. 

As an alternative, you can create a journal entry (JE) to zero out the Profit and Loss (P&L) by the end of FY. This way, you can use it to transfer the account to retained earnings or different account. Here's how: 

1. Go to the Plus icon (+) at the upper right. 
2. Select Journal Entry under Other. 
3. In the Journal date field, enter the transaction date. 
4. In the Account field on the first distribution line, select any account listed in the Chart of Accounts.
5. Enter the transaction amount in the Debits or Credits column.
6. In the Name field, specify a customer, supplier, or employee associated with the line.
7. Continue to enter distribution lines until the sum of the Debit column entries equals the sum of the Credit column entries.
8. Click Save.

For more information, here's a great article you can refer to: Create A Journal Entry. 

If you have other concerns, you're always welcome to click the Reply button. I'm always here to help.