Hmm… I don’t know what’s happening to you but it doesn’t happen to me. I’ve tried copying and pasting in the same material and to another material. It works fine for me.
Greetings.
Since upgrading to UE 4.4 final release (downloaded via Launcher), I cannot use Ctrl-C / Ctrl-V any more to copy nodes in the material editor.
It happens in every project and every material, even in completely new materials.
Unreal editor crashes to the desktop completely and has to be restarted.
Can you please check this - it’s annoying (but temporarily tolerable) to create each new node via the menu, even if you could just copy / paste it.
It also is not possible to copy networks of nodes from one material to another (same crash as above) - that is very bad.
[Edit:]
Work-around:
Disable (toggle) the Realtime Preview in the Material Editor Viewport before pasting a copied node (network). After pasting, you can re-enable the realtime viewport.
This way no crashes happen, but this is not a final solution…hope the devs can find out what’s causing this bug.
Hey SvenK -
Is the Crash Reporter coming up when you crash to desktop? If so, please post the Alphanumeric string that the reporter generates. If it does not, could you post the log files from the project you are experiencing this in, it should be in the Project’s Saved \ Log directory.
Thank You
Do you use the 4.4 final release or the 4.4 preview release ?
I can copy / paste nodes in the BP editor without problems and also everything else seems to work as expected.
But in the Material editor I can reliably crash it every time with copy/paste.
I didn’t have this problem with with UE 4.3.
Thank You and yes could you post your logs as well
Eric
To the Devs: Search for “if (bUniformExpressionSetMismatch)” in file ShaderBaseClasses.cpp, this is where the crash is logged / generated.
Hey SvenK -
We have been trying to reproduce this in house, but have been unsuccessful so far. We feel that their may have been an error in your installation or upgrade of the final release version of 4.4. Can you save and close all projects in the editor and then from the Launcher’s Library, Verify the 4.4 installation (Click the down arrow next to the 4.4 Launch and then Verify).
Let us know if this doesn’t solve your -
Thank You
Verifying didn’t help and didn’t return errors. Still crashing.
I also compiled UE4.4 from source → this one also crashes as described above.
This seems to have something to do with the realtime preview window in the material editor.
Please consider my work-around above and my comment to the Devs. above.
Thx.
Eric, I posted this on the forums as well:
I have just had this occur twice, and for me is caused by trying to copy and paste a “parameter” node, happened when trying to copy a “ScalarParameter” node & a VectorParameter node (both had been named), and crashed immediately on pressing Ctrl-V.
Hey SvenK -
I know this is frustrating, but we have tried on multiple machines and build types in house and can not reproduce this error. Can you or give me a very detailed description of the steps that cause this crash including exact templates used to create the level, materials and assets you are using?
Thank You
No problem, I appreciate your efforts.
1.) Use / start either the UE 4.4 version downloaded via the Launcher or built from source - doesn’t matter.
2.) Create a new project, the simplest one is sufficient (e.g. “Blank”, “A clean empty project…”)
3.) Create a new material and open it in the material editor.
4.) Add whatever node; the simplest node like a scalar constant is sufficient.
5.) Make sure the “realtime rendering” icon in the material editor viewport is selected (the stop watch / clock symbol at the top right side of the viewport has to be orange / selected).
6.) Make sure the node you created is selected. Do a Ctrl-C / Ctrl-V => Crash !
7.) Repeat Steps 1.) to 4.) Then make sure that the realtime rendering icon (described in 5. above) is not selected / gray.
8.) Repeat Point 6.) as described above => No Crash ! You can enable realtime rendering again after Ctrl-V.
It seems that the problem is related to the realtime rendering preview window in the material editor.
The Exception is thrown near the line “if (bUniformExpressionSetMismatch)” in file ShaderBaseClasses.cpp of the Unreal Engine source code.:
TBasePassVSFNoLightMapPolicy shader uniform expression set mismatch for material PreviewMaterial_0/WorldGridMaterial.
Shader compilation info: WorldGridMaterial
Material render proxy compilation info: Compiling WorldGridMaterial: Platform=PCD3D_SM5, Usage=MSM_DefaultLit, BLEND_Opaque, SpecialEngine, TSNormal
Shader uniform expression set: 1 vectors, 1 scalars, 2 2D textures, 0 cube textures, shader map 000000000E295D00
Material uniform expression set: 1 vectors, 1 scalars, 2 2D textures, 0 cube textures, shader map 000000000E121F80
Btw.: I am using an AMD Radeon HD7950 card (newest Catalyst productive drivers V 14.4), Win7-64 SP1 Ultimate, 16GB RAM, Intel 6-core proc.
Well, it seems fixed now for me, I tried the Verify process noted above for the 4.4 editor, it completed, and now my editor no longer crashes like it did in my prev post., so anyways, Thank you! I will let the OP choose whether this should be marked as answer, but I will add a +1 from me! 
Hey SvenK -
Still not having any luck on reproducing this error in house. We have tested it on an AMD machine very similar to your CPU build (memory being a little different). At this point we are suggesting two things, look at your Radeon Driver number (Not Catalyst version) and see if you are at 14.1 (Catalyst can be 14.4). Also Try to uninstall all versions of the editor and reinstall just 4.4 only. If you have already done that let me know.
Thank You
Hi Eric,
I tried everything you suggested; my driver version is 14.100. - no luck.
Don’t try to reproduce this error any more.
For now, I do know the work-around described above, and it’s not a big hassle to use it.
It might just be some very seldom problem with my special system configuration.
Thanks a lot for your help and for trying to reproduce this !
If anybody else stumbles over this problem, it would be nice to leave a comment here or over at the forums to eventually narrow it down a bit more.
Hey -
I am marking this resolved only for tracking purposes. If anyone comes across this problem again, please post your DXDIAG.txt and let me know are we will try to reproduce this again.
We are continuing to investigate this. New users who have this problem please upload a DXDIAG.txt and any Crash Log reports and IDs.
Thank You
Hey guys, I’m having the same, I followed the steps to verify launch and it “backed up files” and finished but I still have the error.
Here is my DxDiag, I am going to try un-installing and re-installing.
This is the crash error:
!Id:8fdfadb5217ce5e081950a0068ff47df
We apologize for the inconvenience.
Please send this crash report to help improve our software.
Update: Re-installed, re-verified and it let me paste a single node, after which the crash re-surfaced 
I upgraded drivers for my video card and everything as suggested above.
Hey SvenK -
Can you upload a DXDIAG.txt?
Thank You