UserAgent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36

Steps to reproduce the problem:
1. click on 'always open with system viewer' (or update to latest version of chrome(?))
2. download pdf files
3. try to uncheck 'always open with system viewer'
4. download pdf files- they'll automatically open in system viewer

What is the expected behavior?
file downloads and doesn't open automatically in 'system viewer'

What went wrong?
File downloads and automatically opens in system viewer (Acrobat DC, for me), 'always open with system viewer' won't uncheck and remains checked regardless of attempts to uncheck it, attempts to clear auto-open settings through settings page, and manual edits to preferences file in C:\users\<username>\appdata\local\chrome, uninstalling a system viewer (Acrobat DC) just means it opens in the next available viewer (Acrobat Pro, for me). 

Did this work before? Yes unknown

Chrome version: 56.0.2924.87  Channel: stable
OS Version: 10.0
Flash Version: 

Saw Mac users were also having this issue recently so it could be some coding based error?