I did a search and couldn't find an answer to this. My hard drive is partitioned in a C and D drive. I installed the pro version 2015 on my D drive and all works okay but I have upgraded to the Mega Pak and I don't think I have enough space to install on the C or D drive. I would like to install it all on an external drive or Install just BIAB and Real Band on the D drive and the supporting files that take up all the space on an external drive. I have seen that BIAB offers that method with their hard drive but I have the downloaded version. If I run everything from an external drive will I have issues other than it runs slower? I want to avoid having to remove a lot of files from my D drive if possible.