Hi,
Hoping that someone can help me with this problem as it's really got me stumped.
I have read many posts regarding problems with Sharepoint 2010 not opening pdf files from IE. Unfortunately none of those issues directly relate to my problem. They seem to be saying that Sharepoint is asking you to save instead of open.
In my situation, when a pdf file is clicked with Sharepoint on premises site, the file will try and open, and then return an error of "The URL you have provided could not be reached. Please verify that the URL is correct and that the network location is reachable". I am convinced this is due to a password issue. We had a separate issue of people being asked for passwords every time they opened a document. When it came to PDF's, if a user pressed Cancel to skip typing in a password, the pdf would open fine. If a password was entered, the error above was displayed.
Now we have resolved the issue of the password prompt, it's possible that Sharepoint is sending the username and password to Adobe reader to open the pdf. And because Adobe is not Microsoft technology, it wont accept the values of username and password and will not open. Also probably why it worked when Cancel was clicked.
In addition I have tried another sharepoint online site, and PDF's open fine in the browser. It's obviously something within the Sharepoint 2010 on premises installation.
Any help would be greatly appreciated.
Thanks