Hi f00by
I'm not aware of any widespread situations of that occurring with company files with regard to the AccountRight 2023.1 upgrade.
I would recommend ensuring that you are on the AccountRight 2023.1 version. This can be checked from within the Welcome window when you first open the software (underneath the MYOB AccountRight - top left). If you are not on that version, do open a local file or the clearwater files. This should prompt the program to be upgraded to the latest version.
Once on the latest version do select the Open a Company file option and select to open the required file to upgrade it.
If you are sill encountering that situation after completing those actions, the next step would be uninstall the version and then reinstall using the download available through the Product Downloads page.