In search of an English word?

I see the word ‘parent’ used in this context.
A is the parent of B, and Users is the parent of A in this case.

Like @dabbler said, the technical term in this case is parent folder.

If the folder “A” is inside folder “B” as stated in the OP, then the path would be :\Users\B\A. So caution, either the “inside” relationship or the path stated in the OP is in error. That said, a folder that is inside another folder is the sibling of the folder it’s in, and the containing folder is its parent as @SavoirFaire & @dabbler noted.

And say “set up the path,” not “set the path up.”

Be sure that the technical level of your user is such that “parent” will be understood. If your audience is not tech-savvy, “preceding” or “containing” or possibly even “higher” ought to convey what you mean. Calling them A and B for illustrative purposes would also help, so the reference is explicit and not relative.

@ETpro; I mistakenly put folder A inside B. I should have been B inside A.

@dabbler, @SavoirFaire:
Scenario: It is required to the user to set up the path to the folder “A”(which is previous to B) – how can I tell this case to the person I am talking to and (s)he doesn’t know about the folders A and B. What would be the general sentence? Yes, “parent” does work.

@Jeruba: “set up” can also be used like.

What do you say about this sentence?

Set up the path up to the previous folder.

Let me try to explain this scenario much clearer.

B is a folder inside A. If a user sets up a path up to the folder A and saves the file, then the files stored in the folder B are visible somewhere in a software.

Now, how can I tell this to a person who doesn’t know about the folders A and B?

I think most computer users would understand : “save the file into folder A”
I don’t think you have to tell them to set the path up to A, or how to get to it. They’d understand from the context that they have to get to folder A to save the file.

Also, ”‘navigate to’ ... folder A” and ”‘go to’... folder A” are common ways to tell the user to ‘set up the path up to folder A’.
If your target audience do not understand ‘parent folder’ and ‘navigate’ or “go to” then you have a different challenge on your hands and may need to include some preliminary material about computer usage material first, to define terms and basic concepts.