I am using Adobe Acrobat X Pro on 64-bit Windows 7. Every time I start a batch optimisation job, and then try to view any PDF file unrelated to the batch job, I can see in Task Manager that another instance of Acrobat has opened, but the file won't actually show up on my screen until the batch job has finished (which can be hours later). Is there any way around this? I tried specifying the "/n" switch on the Acrobat open command, but that did not help.
Thanks for your suggestion. I actually found the solution myself. I edited the wrong registry key. I edited the Open command under AcroExch.Document, which everything seemed to indicate was the correct key, but the correct key is actually AcroExch.Document.7. Now I can open PDFs while a batch is running.