Some common things in App-V 4.6
in fairness, quite good questions. All subjects I cover in my training courses. I would guess anybody else who has a course would cover them too.
Are you using a really old version of App-v 4.6??
Rebase dlls, was used a lot for Citrix stuff. you can read some things on it on the magical wide wide world of web stuff.
Essentially its sort of, kind of, figures out where the DLLs (files) are, then checks if they stacked up in memory, flushes all that out, in case memory address locations don't match. Which could easily happen if you have a sequencer with 2GB or 4GB or RAM, but then run the app on a server with 32GB of RAM.
To make it nice and easy (light and not to techy) i referred to it as 'reshuffling the deck'. Its a bit easier. I have not really seen any issues in recent years that rebasing resolved.