Sorry that my very first post here has to be a question, but I have used Calibre with my Kindle keyboard for two years and on my Galaxy 10.1 for months with no issue. This past week I purchased a Nexus 7 and last night was using Calibre to manage as I always have, but made the mistake of giving Calibre permission to manage my library on the device. I opened the file manager on the device and it only showed a couple of folders.

I goofed!
I looked here and in the manual at the site and could not find a way to reverse the command so I did a factory restore.
If I inadvertently give Calibre permission again by mistake, how do I reverse it? Will the disabling of the plug in be enough?
By the way, great site here, with lots of helpful information. Thank you.