After confronting Sparsebundle corrupt: no mountable file system problem you would no longer able to access disk image which may likely turn into a serious data loss. Any sort of transformation in band files may liable for the emergence of this issue. No matter whatsoever the reason when Sparsebundle corrupt: no mountable file system comes up then inaccessibility might occur to the stored file as well. In order to come out from the problem one need to attach sparsebundle with command Line just using sudo hdiutil attach /path/to/sparsebundle -nomount command. And thereafter you need to launch Time Machine preferences.
Thus you tackle the very issue. But at meanwhile it is so disturbing when you lose the access of important data but with adequate approach the recovery is done successfully. Mac Data Recovery Software is no doubt ensuring you fully data recovery in short span of time. This is a professional tool which can be taken into account by the users for retrieving their missing, inaccessible or lost data effectively. The tool completely get rid of file loss in a user friendly manner. Hope now you have an adequate understanding on how to deal with Sparsebundle corrupt: no mountable file system.