If you want to have an arbitrary path that differs for each user, you need to make it relative to your file, instead of specifying a designated drive letter.
Under File > Manage > Containers...
Make sure your Base Directory is listed as [hosted location]/Files/_your filename_/
It should not be listed as something like:
You may also want to store all of your container data internally (IE under the options for the container field, do NOT check the box in the storage tab that says "Store container data externally")
I am not sure how this affect runtimes, as I stopped using them in v.10, so there could be some sort of other considerations you need to make for v.12 based on how containers have changed completely. You might need to import all of the images from your folder into the runtime itself.