It looks like the registry solution I described above should work and fix this issue (with the downside that you would lose old creature designs). You can try to first remove only the entry with the key that begins with "_CreatureNames" from the registry. That should probably be enough. If not, then remove the entire Evolution folder from your registry. That will be act like a fresh install.
I just uploaded a new Windows version, which should hopefully fix the issue. Can you please follow these steps and the let me know if it worked or not:
(You might not need to do all three of these steps - do them one at a time, try again and stop as soon as the editor works again.)
1. Go to C:\User\YourUser\AppData\LocalLow\Keiwan Donyagard\Evolution and delete the CreatureSaves folder.
2. Open regedit and go to HKEY_CURRENT_USER\Software\Keiwan Donyagard\Evolution and delete the entries that begin with "LAST_CREATURE_DESIGN_KEY" and "DID_MIGRATE_CREATURE_SAVES_KEY".
3. If both steps above didn't fix the issue yet, delete the whole Evolution folder in your registry using regedit.
I just uploaded a new Windows version, which should hopefully fix the issue. Can you please follow these steps and the let me know if it worked or not:
(You might not need to do all three of these steps - do them one at a time, try again and stop as soon as the editor works again.)
1. Go to C:\User\YourUser\AppData\LocalLow\Keiwan Donyagard\Evolution and delete the CreatureSaves folder.
2. Open regedit and go to HKEY_CURRENT_USER\Software\Keiwan Donyagard\Evolution and delete the entries that begin with "LAST_CREATURE_DESIGN_KEY" and "DID_MIGRATE_CREATURE_SAVES_KEY".
3. If both steps above didn't fix the issue yet, delete the whole Evolution folder in your registry using regedit.