遇到 pdf 打不开 couldn't load plugin cannot view pdf file

原因：Adobe Flash Player   is not updated. 

最简单的方法:

1. Go to here: 

https://get.adobe.com/flashplayer/otherversions/

2. choose the right system and system version - 选 PPAPI 

3. download and install. But be careful, it may have some other applications to be installed at the same time, if you see more than one loading bar, stop the installation, it will allow you unselect the unwanted software. 

4. After the installation, restart the computer, now you can load or display pdf files. 

5. 有一个方法检测 components 是否是最新版： 

如果是 google chrome:

chrome://components/

如果是 微软的 edge: 

edge://components/

直接点击 或者  copy paste 到 浏览器里就可以查看了