Deleting an account permanently removes that account's records from your file. Once you delete an account, there's no way to recover the account or the information about your transactions that it contained. In addition, Quicken deletes the account name from the Category field of all transactions that have transfers to the account. These transactions appear as uncategorized transactions in reports.
In most cases, we recommend that you hide an account instead.
When you click Done, Quicken transfers all cash transactions into the investment account's transaction list and deletes the existing linked checking account.
If your linked checking account included transfers from other cash flow accounts, these may affect your ending cash balance. You can either restore your backup file (recommended) or resolve the difference by editing the cash transactions in your investment account.