I undid a reconciliation but checks from that month still say cleared?? How can I fix this?

Hello, DwyerFP. 

I'll help you out in correcting the unmarked transactions so you can reconcile your account properly. 

You'll want to use the Undo Last Reconciliation button again. It's likely that the process did not go through successfully (due to data issues). 

If it still doesn't unmark all of the transactions from the last period (or if it prompts you that there is no reconciliation to undo), you'll want to fix this by doing the Rebuild/Verify tool. It can still work on QuickBooks Pro 2012. 

Here's how: 

1. Go to Files, then hover on Utilities.
2. Select Verify Data.
3. Follow the prompts to continue with the verification process. 
4. Once done, go to the Utilities menu again.
5. Choose Rebuild this time.
6. Follow the prompts to let QuickBooks fix the data issues. 

Alternatively, you'll want to go to the bank's register and manually unmark those transactions. Here's how:

1. Go to Lists, then select Chart of Accounts.
2. Double-click on the bank to open the register.
3. Find a transaction, then click the check mark column until a blank box appears.
4. Do this until all of the transactions are unmarked for reconciliation.  

If you need a guide in reconciling your bank, you can check this article: Reconcile an account in QuickBooks Desktop.

After dealing with the reconciliation issue and reconciling your accounts properly, do you need help with something else? I recommend checking out our articles from the QuickBooks Desktop articles list page (they still work for QuickBooks 2012).

They can guide you in recording other transactions, help you manage your lists and more. 

I'm still with you if you have other concerns with reconciliation. Do you need help in other areas in QuickBooks? Let me know and I'll assist you again.