How to disable the built-in PDF viewer in Google Chrome
By default, Chrome uses a built-in PDF viewer to open PDFs.
If you disable the built-in PDF viewer, Chrome will use Acrobat Reader to display PDFs.
1. Open this page in Google Chrome Web Browser.
2. Enter chrome://plugins into your address bar.
3. Scroll down to Chrome PDF Viewer.
Click the Disable link.
That's all there is to it. PDF Files will now open in Acrobat Reader.
To switch back to Google Chrome built-in PDF viewer, reverse step 3 and click Enable.