I have problem with with changing widget (led) properties. I’ve tried exactly what is shown in https://www.youtube.com/watch?v=yfs6Cut7GDE
I’ve tried change Led color but I’ve got error message ‘class BlynkEthernet’ has no member named 'setProperty’. I tried to reinstall library which was recommendation as comment in video, but it doesn’t help me.
Any other ideas?
any code?
Actually no, I will paste it when I will be @home 
But I think it is not necessary because I used command from video
Blynk.setProperty(V6, “color”,"#CodeOfColor");
And there arduino return error message
Always necessary… because we don’t want to have to run around looking up the “code/command from video” then try and guess what changes you might have made that prevent it from working, etc…
Or perhaps you have literally taken the code as you posted… without actually modifying the #CodeOfColor as required for the IDE to understand what you want. HINT: #CodeOfColor is the incorrect answer 
Documentation to the rescue…
Ok I find sollution, it work on my company laptop (WINDOWS) but not working on my home computer (LINUX)
And here is code which I used: Blynk.setProperty(V6,“color”,"#ff00cc");
Depending on what you mean by “it”… the OS of your computer shouldn’t make any difference at all in how a program runs on an MCU.
I think you need to provide more details on what you are doing, expecting and having problems accomplishing.
I know that couldn’t depend on OS but on Windows it works and on linux no.
I’m testing it on Arduino Mega 2560.
I need to change color of LED diode which signaling status of garage door (open/close).
I don’t want to put whole code, because it has about 1k lines
in short it is like this
if(stav_garazovej_brany == HIGH) Blynk.setProperty(V6,“color”,“DC143C”);
else Blynk.setProperty(V6,“color”,"#00FF00");
Missing the #
And the code you write in the IDE should be operating system agnostic, so if you are having problems in your Linux PC, then it is due to something else entirely and not a Blynk command issue.