Cannot Open .Sparsebundle
I was able to solve the problem myself, in few super easy steps, here's how:

-Right click on user1.sparsebundle -> get info, then make sure your user has the permission to open it
     (if not then click on the lock at lower right of "user1.sparsebundle" info window enter your password and add the user you want it to be shared with.)

-hook up a new external disk to mac and set it up as a time machine disk. 

-copy the "user1.sparsebundle" into it 

-once files are copied, open external hard drive and open "user1.sparsebundle" file 
( you may need to enter your password do so and files will be mounted as a disk in your finder ) 

I think the key point is to have an external hard drive set as time machine and copy sparsebundle file into it.