Anyone tried this yet? I wanted a separate installation for F1 2013 single player mod due to the required AI strength. It is possible to do a new install, or alternatively you can copy an existing install and just amend the directory in the data.path file in the core directory. Don't know if this has been mentioned before, if it has, please ignore my ramblings.
Not tried two installs of the same version but I still have old versions on my HDD and 342 (for example) fires up fine.
Separate installs works fine as does copying installs. The only thing to watch is that Mod Manager stores the Packages and Working Dir paths as a global variable in the Registry. So everytime you start it, you need to ensure you're working in the right directories.
It would be best if you can use same packages folder for both, it can be a PITA if you don't. Really though, I don't see the problem of using the same folder. That is how I always run the stable and a beta build.
Yes, i usually use shared Data folders, but, if i understand what the OP wants to do, using shared Data folders (or Packages only) is not the way, because all the contents will be shared between both the instances.
