If your models appear red in the scene viewer and aren't selectable it indicates that these models are no longer valid and will be archived the next time you open Arkio. Models can go invalid during corrupted modeling operations or when updating from older version of Arkio.
models that are marked red will be automatically moved to the InvalidUserModels folder and won't be visible the next time you open Arkio. If you wish to recover these models you can check the history models to recover an older version of that model that was still healthy. In case you need to recover an invalid model that does not have a valid history backup you can get in touch with us at email@example.com.
Everything in Arkio is automatically backed up in history. You can go back in time to find backups of files that became invalid. Once history mode, the models you previously worked on can be restored by selecting the model (yellow highlight) and pressing the restore button.