Kindly please expand on what the root cause is and what the 'fix' might be
I don't believe it is simple to fix. But you are right of course, the root cause is what you should aim for.
The west has been trying to do that for decades. Things just get worse and worse. What do you propose?
The West does not currently have much of a problem with violent separatism. Maybe someone got into a bar fight over Catalan independence or Brexit, but all recent conflicts I'm aware of were relatively peaceful. If you compare this to the situation in Northern Ireland, I'd say things have gotten much better.
yougoslavian people will beg to differ. Civil war in a european country leading to the partition of the country into multiple states based on ethnic and religious criteria happened in europe just 25 years ago.
I have a slightly different perspective on what counts as "recent", most likely because I am younger than that. I also looked up the Troubles for my previous comment; apparently they officially ended in 1998, which is even more recent. Take my comment as referring to the last 20ish years when I talk about things getting better.
One might argue that Yugoslavia, then recently emerged from decades of dictatorship and still a communist Eastern European country, was not part of the ideological West at that time.
What is the simple way for the Chinese government to find the root cause of muslim terrorism and fix it? The only simple fix (as in simple vs easy) would be genocide or giving them their own independent state. The first option is horrible, and the second is not in the interest of the Chinese gov.