How do you unlock previous accounting years? The password that I use to log in is not working when prompted for password when I try to change previous years stuff.

Welcome and thank you for taking the time to reach out to us here on the Community page, @RR6,

To unlock the previous accounting years, you have to use the password that was set up under the Account and Settings page and not the login password. If you've forgotten the closing date password, change the password by entering a new one and confirming it.

To update the closing date password:

1. Go to the Gear icon, then tap on Account and Settings under Your Company.
2. Click on Advanced at the left pane.
3. Hit on the pencil icon in the Accounting section.
4. Under the Closing date, enter a new password under Password and confirm it under Confirm Password.
5. Tap on Save, then Done.

Once completed, use the new password when updating your previous transactions.

You can also take a look at this article for additional reference about editing closed books in QuickBooks Online: Edit your closed books.

Add a comment below if you have any other questions. I'm a post away to help. Wishing you a good one!