This is due to an issue with Local Classic. You can read about this in more detail in this FAQ:
It might make sense to try and install Local Lightning (the most recent, 5.x line of releases) from the releases page:
Once that’s installed, you can try restoring the sites to a new ones in Local using either a backup of the site, or try using the files for the site by following the steps outlined in the “Restoring From Only Local Site files” section of this help doc: