Try This Worked for me...
..1st install the driver software
..then restart your computer and open "MMX 352G USB Manager" from desktop
..open Device manager
1.Device Application Interface
2.Device Diagnostic Interface
or try uninstall any other with a Yellow sign error device
..then Search for hardware changes
..after completion exit modem Software [MMX 352G USB Manager](in taskbar icon-select exit ) and re open it...
...It will do..