Hi Yelka
The issue is whether the Balance Sheet balances or not. If the Balance Sheet balances, then the Historical Balance was deliberately set (by someone) and should be corrected under Setup > Balances > Account Opening Balances.
If the balance sheet is out of balance by the Historical balance amount and the fix suggested does not fix it, the file will need to be repaired by MYOB or others such as MYOX Services.
What causes Historical Balance errors is when someone plays with the Accounts List, changing accounts from Header Accounts to Details Accounts and vice versa. AR2024 does not handle these changes correctly.
Regards
Gavin