[visual studio] every time you open a script of unity3d, a new vs2017 will be automatically reopened

Problem description ：
As the title , Each time the Unity3D Open one in C# Script , Whether the script is in the same solution or not , Will reopen a new VisualStudio2017, I'm so angry , Bloggers are really puzzled ！

More Than This , Every time open VS, This prompt box also loads very slowly ,VS It's still open , Clicking cancel will open a new empty VS, I'm so angry ！

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resolvent ：
After ten days of searching , Finally the problem was solved , Note that this method is tested by bloggers , Different people may have different situations ：
1. The first is my solution ： stay VisualStudio2017 in , In Solution Explorer （ On the right side ） in , Choose your project , Right click , choice “ Set as startup project ” , Perfect solution ！！！
2. Then there is the solution circulated on the Internet , But not for bloggers , Let's also share ： Open the folder where your project is stored , Delete .sln Final document , This file is VS Index of the project , Re in VS Open the project in and the file will be regenerated , Don't worry about the impact on the project .