Cylinder unwrap help

Well, my guess is: as you've used a Cylinder Primitive, that already has  UV's on it by default:

when you put Seams on it, it will still use the 'old' UV's, unless you Unwrap it again with the new Seams.

But maybe I completely misunderstand your question...the screenshots don't help me understand the problem...this is just going by the text..

but i unwrapped with new seams...

You know that you have scaled the X and Y by 2, don't you?

That means the Texture will be repeated twice around the Cylinder, thus giving two seams...

it always creates multiple seams, even when scale is 1

Maybe it's something like this?

The blue line is where the left and right side of the image  meet and win a not seamless texture, that would be a visible seam..

I have a material with an image texture on it. I tried smart uv project, or cylinder project. But with every projection, the seams are always at the same spot

Could you make a Screenshot with the 3D View (Cylinder in Edit Mode)and the UV Editor(with the image) open?

I dont have the image in image editor, its just as a texture node in material

So, open it up in the UV Editor (or in the Image Editor, should work as well); where it says Untitled, change that to your uv3.png (it's in the dropdown list: down arrow left of the name)

Oh, and put the 3D View in Rendered Mode, so I can see the texture on the cylinder

And Unwrap it with your Seams, not with Smart UV Project.,..

And now? I am very happy that you help ;) thanks

The image underneath the  left rectangle in the Image Editor is being projected on the 'middle' part of your Cylinder:

At the moment this is mostly empty space..

Change the Image Editor to the UV Editor, so you can fit the rectangular area around the text.

Thanks, it worked ;)