Hi Wendy2018,
We totally understand your feelings, and we apologize for the inconvenience caused by the issue with unlocking and locking previous periods to access invoices. Our team has addressed this issue in the latest AccountRight update. You should now be able to print, preview, email, or save sales invoices without unlocking previous periods. Please update to the latest version of AccountRight to access this fix. For more details, you can check the release notes here: AccountRight releases.
Feel free to get in touch if you're still encountering issues.
Cheers,
MYOB