If you've created a Sheet View, customized it then tried to save the configuration:
... but the dialog below is displayed:
... Then you've encountered a bug in this ASE Civil subsystem.
So, What 'Does' Work?
As of the date of this post, you can only save a Sheet View configuration for a 40-scale, single, continuous display. This would be the [svL1] ribbon tab. No other Sheet View configurations can be saved as a project prototype.
Why is This Broken?
We changed the way ASE Civil saves Sheet View configurations. Previously they were saved to the local ASE install folder in "C:\Program Files". If someone saved a configuration, only they could see it. For others to use it, the folders had to be manually cloned to each computer.
Now, when ASE Civil saves a Sheet View, it's saved to the ASE project folder. The configuration immediately becomes a template for the entire project.
Nice, right? Yeah, but we couldn't finish the coding for the rest of the configurations and scales. So unfortunately, this only works for the 40-scale, single road (non-split) configuration.
So to get with the whole "sharing" movement, we had to completely change how ASE saves the Sheet Views. There was a lot more to it than just changing the target location. We were also "refactoring" the source code of the Sheet Views subsystem to make the whole thing run faster and more reliably. After all; Sheet Views is the oldest subsystem in the entire application! Ironically, it's also the most heavily used as well.
When Will it be Fixed?
We're actively working on repairing this, since we just got our complaint about this issue.
Expect an update around July 9, 2018 that includes a repair for this specific problem.