Hi .
Take a look at this post on the Answerhub (or run a search for others): Project fails to compile in VS after migration to 4.11 - Pipeline & Plugins - Epic Developer Community Forums
Their was they they were using plugins that were not available yet in the new release.
If you need further help, please submit your own Answerhub post.
Cheers
Thank you Stephen 
That was it. Substance Designer/Painter plugin was causing the problem. I think it’s worth pointing out that even though I disabled the plugin when asked while trying to open it in the UE4 Editor it doesn’t remove it from the project file.
I’m now getting an unresolved linker error:
error LNK2001: unresolved external symbol ": virtual void __cdecl IGameplayTaskOwnerInterface::OnGameplayTaskActivated(class UGameplayTask &)" (?OnGameplayTaskActivated@IGameplayTaskOwnerInterface@@UEAAXAEAVUGameplayTask@@@Z)
[EDIT]
Adding GameplayTasks to the Build.cs file resolves the problem ([4.12 preview1 ] Strange link error in my project - AI - Epic Developer Community Forums)
Now to checkout the new improvements 
http://s33.postimg.org/y3mmcwekr/Image1.jpg
I like sequencer and ability of recording gameplay although it is still quite messy and have problems, the one on which I came across is
…project from version 4.11.2 recorded gameplay, in the editor looks fine, but when we want to render ,something is messed up like it does not take into consideration all rotation… I hope it will not be hard to fix
Ahem, GoogleVR will work in next preview and release version, I presume?
I bought Nexus 6P to test daydream after your stream and now I am extremely disappointed ~_~
Headstart, heh.
@ and @Vaei
Found the solution to your a few posts up from your first post courtesy of Hobson (was looking for another and came across it):
Yeh we both did that but it didn’t download the source. They’ve recently added a new option to the Launcher when downloading though, so it works now. For some reason you needed Starter Content and Templates for the source to download.
Yeah, all solved now though thanks to the launcher update.
The known issues is only with Binary version (from launcher), next preview/release should work fine in binary.
however it works with github now
Hello guys
I want to know is there any support for Google Cardboard in ?
Why not some texture expressions like Rotator or Fresnel are not added to MinimalAPI ?
Any of UE-29885 being fixed for ? Blueprint context search input starts unactivated - Blueprint - Epic Developer Community Forums
It’s a real time waster.
hi,
we got a linker error for libeay32.lib under preview 5.
We are using OpenSSL, under version 4.10 it was working.
Any idea how to fix this?
I hope you can get this thing fixed in release 
it wasnt fixed correctly, code is missing. please carefully! i depend on that bugfix!
Is there any news on UE-3948? I feel like its an major for fast paced multiplayer games. It makes our game look laggy to server ;(
agreed, needs fix!
I saw somewhere that the is fixed and introduced a new setting to help tune it p.NetEnabledListenServerSmoothing . Not sure what the trade offs are may need a dev or support member to help clarify.
It has returned, my .cpp files are gone again. I guess I’ll install starter content or something I don’t need temporarily.
Edit: Noticed when installing something else there’s now “Engine Source”, I take it that the .cpp are now optional and I just need that then. Hah, sorry! You can ignore this.
Any word on how to address the following packaging error that has cropped up in 4.12p5?
[2016.05.30-19.38.20:730] 0]LogWindows:Error: === Critical error: ===
Assertion failed: ModuleManager.IsModuleLoaded(ModuleName) [File:C:\Users\GeorgeDev\Documents\Unreal Projects\UnrealEngine\Engine\Source\Runtime\Core\Modules\ModuleManager.h] [Line: 240]
Tried to get module interface for unloaded module: ‘OnlineSubsystem’
