When I open the Umbraco (7.6.3) backoffice, I'm unable to view or make changes to templates. It seems like other functionality is unaffected, and I can create & edit specific pages. However, attempting to open the templates themselves just leads to a white screen. This problem exists across browsers:
[![A screen, not showing what it's supposed to](https://i.stack.imgur.com/xdKSz.png)](https://i.stack.imgur.com/xdKSz.png)

Other screens render just fine:

[![a normal looking screen](https://i.stack.imgur.com/BfaQg.png)](https://i.stack.imgur.com/BfaQg.png)

What gives?

Checking the console when attempting to load gives an interesting error:

```
Error: Argument 'Umbraco.Editors.Templates.EditController' is not a function, got undefined...

```

[![enter image description here](https://i.stack.imgur.com/VnfF1.png)](https://i.stack.imgur.com/VnfF1.png)

---

Resolution:
-----------

The issue seemed to be caused by outdated files in the `Umbraco` folder. Copying most directories over from `packages\UmbracoCms.7.6.3\UmbracoFiles\umbraco\` seems to have done the trick.  

Looking at the changelog, it seems like the `JS` folder was the most influential in getting this fixed.