Chrome and Firefox each use their own default PDF viewer instead of Adobe Reader to view PDF files.
Infinite Campus sometimes has issues with these viewers and won't let you upload a PDF document, saying that the default viewer may corrupt form data.
To switch to Adobe Reader instead of the default viewer:
In the address bar when in Chrome, type Chrome://plugins.
On the resulting page, disable the Chrome PDF viewer and enable Adobe Reader by clicking on the disable and enable links, respectively. That's all you need to do, there is no save or anything like that.
Open the Options dialog with either Tools, then Options menu, or clicking on the menu icon in the upper right and selecting Options.
Select the Applications tab.
Under Content Type, find the line for Portable Document Format (PDF), and change from Preview in Firefox to Use Adobe Reader.