Symptoms

I'm using K2 Blackpearl 4.13060.13204.2

1/ We develop a x64 web app using below K2 dlls:
- SourceCode.HostClientAPI.dll
- SourceCode.SmartObjects.Services.ServiceSDK.dll
- SourceCode.Workflow.Client.dll

Unfortunately, we only have those dlls in x86, can you provide us those dlls in x64 ?

2/ Recently I’ve installed VS 2015 with .NET Framework 4.6, then, I found out that I can’t open any K2 objects such as smart object, K2 workflow anymore. Please could you provide a workaround or solution?

- In VS2012, it shows Incompatible error: see VS2012.png attached
- In K2 Studio, it shows error when
 

Diagnoses

1/ 32 and 64 bit dll's are both installed.

2/ Incompatible versions of BlackPearl, .NET and Visual Studio.
 

Resolution

1/
1) The 32-bit version of K2 assemblies can be found in:
C:Program Files (x86)K2 blackpearlin
2) The 64-bit version of K2 assemblies can be found in:
C:Program Files (x86)K2 blackpearlHost Serverin - this is the AMD64 file

If you are confused about which version you are looking at you can use a program that will dump the information for you within the assembly, such as Dumpbin which is a visual studio tool and the version should be apparent somewhere near the top of the dump.

Also, you should be able to get locations of 64-bit copies of the assemblies from the GAC, and here is a helpful link on how exactly to do that and then place those assemblies where you need them:

http://blogs.msdn.com/b/johnwpowell/archive/2009/01/14/how-to-copy-an-assembly-from-the-gac.aspx

You may also want to have a look at the "Enable 32-bit applications" flag in IIS Application Pool.

2/ compatibility matrix:
http://help.k2.com/blackpearl/support-matrix

It looks like your client environment is not compatible with 4.6.6.
Only 4.6.11 supports VS 2015 and .NET 4.6, so you will either need to downgrade your VS to 2012 and .NET to 4.5, or upgrade your K2 environment to 4.6.11.
If you downgrade your environment, I'd suggest running a repair install of the 4.6.6 client tools on your client machine.