突然就不对了。

解决方案：

I had the same issue, after a few days of search found a fix that worked for me

WARNING: this WILL reset blend settings!

go to C:\Users\<user>\AppData\Local\Microsoft\Blend\15.0_c2edcfdc

and delete privateregistry.bin

launch blend, the ‘setting things up‘ screen will appear, after its done (took ~30 secs for me). Blend setting will be reset,

But it would work as expected from this point on

参考：

https://developercommunity.visualstudio.com/content/problem/36026/blend-for-vs2017-crash-on-startup.html

Blend for VS2017 已停止工作- Blend for VS2017 has stopped working