How to resolve imbalances and orphan transactions in Gnucash?
The GnuCash manual has a page with examples of opening new accounts. The tl;dr is: use the Equity:Opening Balance to offset your original amounts. The further explanation from the GnuCash page is: As shown earlier with the Assets:Checking account, the starting   balances in an account are typically assigned to a special account   called Equity:Opening Balance. To start filling in this chart of   account, begin by setting the starting balances for the accounts.   Assume that there is $1000 in the savings account and $500 charged on   the credit card. Open the Assets:Savings account register. Select View from the menu and check to make sure you are in Basic Ledger style. You will   view your transactions in the other modes later, but for now let’s   enter a basic transaction using the basic default style. From the Assets:Savings account register window, enter a basic 2 account transaction to set your starting balance to $1000, transferred   from Equity:Opening Balance. Remember, basic transactions transfer   money from a source account to a destination account. Record the   transaction (press the Enter key, or click on the Enter icon). From the Assets:Checking account register window, enter a basic 2 account transaction to set your starting balance to $1000, transferred   from Equity:Opening Balance. From the Liabilities:Visa account register window, enter a basic 2 account transaction to set your starting balance to $500, transferred   from Equity:Opening Balance. This is done by entering the $500 as a   charge in the Visa account (or decrease in the Opening Balance   account), since it is money you borrowed. Record the transaction   (press the Enter key, or click on the Enter icon). You should now have 3 accounts with opening balances set. Assets:Checking, Assets:Savings, and Liabilities:Visa.