Illegitimate posting occurred at the beginning of both Sept 2020 and Oct 2020 distorting month end balances Nov unidentified postings replicated earlier chek posting

Let's review what is happening here, st-thomasmorepar.

Duplicates might come from the Banking page or a recurring transaction template. Let's see which one is causing the unidentified postings.

There might be bank transactions that were Added instead of Matched . Here's how to check the transactions:

1. Select Banking/Transactions on the left menu and go to the Banking tab.
2. Go to the Categorized section and review the transactions.
3. You can Undo the incorrectly added bank transaction.
4. Go to the For review section and match the bank transaction to the existing one in QuickBooks.

You can also use this link for reference: Categorise and match online bank transactions in QuickBooks Online.

If everything is categorised correctly, we can review the recurring templates. Here's how:

1. Click the Gear icon in the upper-right corner and select Recurring transactions.
2. Click the Filter button and select Scheduled in the Template Type field.
3. Select All in the Transaction Type and the Location fields.
4. Click Apply and review the templates. These might be causing the transactions to duplicate.
5. You can Edit the template and change the Template Type to Unscheduled or Reminder.
6. Save the changes.

You can also browse these links on how to manage the recurring template: 

• Create recurring transactions in QuickBooks Online
• Edit a recurring template

For the duplicate transactions that occurred due to the recurring templates, you'll have to delete them manually.

1. Select Accounting on the left menu and go to the Chart of Accounts tab.
2. Look for the affected account and click View register or Account history.
3. Click on the duplicate transaction you want to delete.
4. Select Delete and click Yes to confirm the action.

We'd like to know more about your concern if none of what I've mentioned above suits your situation.