Interesting.I've used ES2 for many years and never had the problem. It happened immediately upon installing ES4.Seems to me that LCD should not rely on Acrobat being installed; I have not seen that mentioned in any system requirements.So even though I have Acrobat 10 and 11 available, at this point ...

I found a number of threads on this reaching back two or more years, but no definitive answer.I have a newly installed LCD ES4.I  have made sure the Adobe Reader add-on is enabled in IE.Reader DC is installed. (I can also install Acrobat Pro XI if needed).Still, the PDF Preview (F5) command is greye...