I’ve had this happen on two separate machines now. A quick search put me in the right direction .
For me, quitting Xcode, renaming it, and restarting it worked. No need for terminal commands, no need for rebooting.
From this... to this
Xcode Plugins
Install the Alcatraz (http://alcatraz.io) package manager to get these.
https://github.com/neonichu/BBUFullIssueNavigator
Shows the whole error/warning in the issue navigator instead of a single line.
https://github.com/yuhua-chen/MCLog
Allows you to filter the console by a regular expression.
https://github.com/markohlebar/Peckham
Add imports from anywhere in the code base - press Cmd+Ctrl+P to pop up a window which has autocompletion for your headers.
https://github.com/onevcat/VVDocumenter-Xcode
Fill in a quick documentation template.
https://github.com/kinwahlai/XcodeRefactoringPlus
Additional refactoring tools. Still not as full-featured as some IDEs but it's a case where every little helps.
Tools - Unity
It took a while but I think I'm finally feeling comfortable working in Unity.The other night I built a minimum viable prototype of one of my iOS games over the course over just a couple of hours. I feel like I'm still learning the flow of the engine, particularly with regards to threading, but there's a lot of power and potential to be tapped and getting started with it is easy. That said, I do miss the more advanced debugging tools I get with something like IntelliJ, or Xcode. And MonoDevelop is pretty awful ;)
Tools - Omnifocus
Of all the productivity tools I've tried, Omnifocus is the one that's come closest to sticking. It helps that I do most of my work on Macs so I don't usually find myself without access to it. That said, I do often go a few days without checking it or adding new items and I am doing a lot of personal game development work on Windows. It feels like there's a habit I have to develop. All too often, the thought is immediately followed by the action. That's satisfying but not always the best use of time. For a start, there's a number of things I've thought of which, given a little distance, were nowhere near as good as I thought they were at the time.
Still, I just can't develop a habit of maintaining the list and I've not get items in there that are no longer applicable from December. I'll give it another shot but I fear I've spent so much time working by holding what I need in my head (plus pen and paper) that I've trained myself to that mindset. Then again, I used to write code in a text editor because IDEs seemed so much more cumbersome and I wouldn't go back to that for serious work. Though, in all honesty, I was mostly working with J2ME and DoJa at the time so learning all the APIs by heart was actual feasible. I do know that when I have my tasks to hand I can be a lot more efficient so I do want to make it work.
I think I'm going to give it one more shot - read some guides, and schedule a block of time to try and figure out a way to make it work for me... If that fails, maybe I'll just resort to a pocket notebook and pen ;)
Tools - Blender
I'll never be an artist. However, it's often useful to have some ability with the various asset creation tools. Blender, being free, is a very good way to create some 3D assets to test out ideas and/or build up something basic. More experienced artists may well have access to something more professional like Maya, or 3D Studio Max. That's not to say that Blender is less capable though. For my needs, it's perfectly usable.
Creature - based on the Lynda.com Blender 2.4 Essentials course.
I've no experience with other modelling tools (beyond some dabbling with Sketchup) but, with my limitations in mind, and a bit of thought about how to approach it, I've created some passable assets to use as placeholders. I've still a lot to learn about texturing, and more advanced modelling techniques and it's possible I won't get there but that limitation is with me and not the tool.
The interface is a little off-putting but there is a lot of power there. Following along with a video tutorial helped to begin making sense of it. Being able to filter out the stuff I don't need broke that initial mental paralysis. Knowing how to get back to the default state was also a big help.
The tools I mostly need access to
There's plenty more to learn so I'll follow this up as I do more with it.