We create new projects from a set of "prototype project" model files, one for each discipline, that are already set up with worksharing and standard worksets and are cross-linked to each other. Models are opened detached from central and then saved to the project folders as central models and the links are reloaded from the project-specific models.
There are six levels in (most) of the prototype models, and the levels in the other models are monitoring the levels in the architectural model, since the architects usually go first. Provided they move/rename the levels in the starter file, it only requires a Coordination Review to get the other discipline models to match the architectural model. (Some projects have more levels, which then need to be added manually.)
I was setting up the other models for a project in which the architectural model was already created, and the process above worked as expected until I got to the structural model. The architects had renamed ROOF to PENTHOUSE ROOF and LEVEL 4 to ROOF. For reasons I did not understand, the Coordination Review renamed ROOF to PENTHOUS, but I was able to change the name and get the monitoring straightened out. The problem was it refused to rename LEVEL 4 to ROOF. I thought may be it was an order of operations thing at first - maybe it was trying to rename LEVEL 4 before it renamed ROOF. But even after I got the PENTHOUSE ROOF level renamed correctly, it still would not rename LEVEL 4 to ROOF, even when doing it manually.
Revit kept claiming that the name ROOF was already in use. We have a Level Schedule in our files, to make checking the names and elevations of levels in a file easy, without worrying about whether a given level's extents will make it show in a given elevation or section - there was no level named ROOF there. I opened Dynamo, and added the Level node, which allows you to select a level, and it did not offer a level named ROOF in the drop-down. I synchronized, closed and reopened the file, hoping that might shake some phantom memory of the old ROOF level out of its system, with no success.
Then it dawned on me that when I renamed the old ROOF level to PENTHOUSE ROOF, it asked me if I wanted to rename views. I clicked on No*, so there was a plan view associated with the PENTHOUSE ROOF level called ROOF. I wondered if that was the reason why Revit would not let me rename LEVEL 4 to ROOF. I was going to rename the views eventually, so I did that and then tried to rename LEVEL 4 one more time. It worked! So it was the fact that there was still a view associated with the PENTHOUSE ROOF level that still had the old level name as the view name that prevented reusing that old name for a different level. I am writing this here in the hope that the next time I run into this, I will have a vague memory of having the issue before, and will search my blog to see how I solved it.
* - I almost never let Revit rename plan views when the name of the associated level is changed. That only changes view names where the entire view name is the level name, and we have many plan views in most models that have the level name in the view name, with additional text. Those will not get changed; I find it easier to use the Dynamo graph I wrote to search for a given string in view names and replace it with a different string when none of the views have had the name changed.