I'm not familiar with how it worked in Quicken Windows, but I can take a stab at what you need to do in Quicken Mac.
Add Share or Remove Shares transactions in your investment account allow you to create (or remove) shares out of thin air to get to a correct number of shares of a security. Add Shares lets you specify the date the shares were aquired, and Remove Shares allows you to specify specific lot(s) of shares to be removed, if you know why and when your share balance is off. If you don't know, and are just adjusting your share balance to be accurate as of today, then just be aware that you won't be able to rely on Quicken to accurately track the sale of individual lots of the security on a FIFO or LIOF basis.
To adjust the cash balance in an account, you need to use a banking-type transaction, where Type=Payment/Deposit. Such transactions are now like transactions in cash and credit card registers. To adjust cash, use Category=Adjustment and add or remove whatever amoutn is needed. Transacitons with the Adjustment category are ignored by Quicken Mac in income and expense reports, so they allow you to create (or remove) cash out of thin air.
Post back if that doesn't address what you're needing to do.
