I'm using Enterprise. Balance sheet is showing incorrect bank account balances.

I'm using Enterprise and have a number of different companies set up. Figures in the balance sheet are incorrect, the actual general ledger balance is ok. If I switch from multi to single user after the report is collated, the balances change to the correct amounts. Seems to be only bank account balances. I've tried verifiying and rebuilding data but it won't fix the problem.