This is a Unicorn/Rainbow error that occurs when the item being saved (serialized to disc) does not have its parent item serialized.
This indicates that you are using Unicorn not only on your local machine, but also on your development server. In general, in most development processes there should be no reason to use Unicorn on a development server, especially with Sitecore data providers patched (see
Unicorn.DataProvider.config). So make sure Unicorn's binaries and configuration don't get deployed. Apart from fixing your issue, your deployments will become simpler and cleaner.
If you do need to use Unicorn in that environment, make sure that you also maintain an up-to-date copy of your serialized items in Unicorn's folder. You can do that in two ways:
- deploy serialized items together with the application;
- or, in case the Sitecore databases are already up to date, use the Unicorn Control Panel to manually serialize all items to disc.