I already did that and reported the results (It works).

I also think it is somewhere in my browser settings.

I just have no idea where to look.

My system says "No extensions installed".

Is an extension different than an add-on?

https://www.irs.gov/pub/irs-drop/n-17-18.pdf

http://www.analog.com/media/en/technical-documentation/data-sheets/ADF4360-8.pdf

When I type a url that ends in "-8.pdf" it appears that something like a spell checker changes it, in certain instances, to "-8-pdf" which ends up with a 404 can't find.

I have confirmed that spell checking is off (although I don't expect spell checking to impact the address bar as I think it is supposed to be effective only for text boxes within a web page).

If I right-click a link that ends in "-8.pdf" and select "Open link in new tab" the same thing happens.

If I right-click a link that ends in "-8.pdf" and select "Open link in new window" the same thing happens.

If I right-click a link that ends in "-8.pdf" and select "Open link in private window" it does not change the url and the private window finds the file and opens it!

So, I have a workaround, but it worries me that there is something going on I don't understand.

I have absolutely no add-ons.

It doesn't appear to happen with any other urls. A link that ends with "-{x}.pdf" where {x} is replaced with any other character than 8 will happily find and open the file as a pdf in the browser.

If somebody could suggest where I can start looking for the source of this it would be appreciated.

Thanks