
Registry issue – This was mitigated in the recent Adobe Reader version, but if you’re using older versions, you might need to do some registry fixing (either manually or by relying on a 3rd party fix that replaces the bad registry value automatically).Īs it turns out, one of the most common culprits that might end up causing the PDF Preview Handler error is an Adobe Reader setting called Internet Auto Detect.

To fix the issue, you’ll need to access the Adobe Reader’s preferences and force it to become your global PDF handler. Adobe Reader is not set as the Default PDF Handler – If your default PDF viewer is not configured to be the default PDF handler and the PDF thumbnail preview feature is not enabled, expect to see this error in when attempting to preview PDF files in Outlook.In this case, you can fix the issue by forcing Adobe Reader to run in Compatibility mode with Windows 8.



Internet Auto Detect is Enabled – As it turns out, one potential cause with the potential of causing the PDF Preview Handler error is a setting called Internet Auto Detect.
