This solution is for those who will face the same problem:
To fix same problem on my S4 mini I've tried:
- Numerous PCs and USB cables
- USB debugging (& Stay awake & Unknown sources) checked and unchecked
- Unmounted & remounted SD card
- Asking the PC to look for new hardware
- Removed and re-installed PC drivers
- Dial *#7284# or *#0808# and set MTP+ADB USB Setting
Nothing help me.
However, thanks to Google, I have the solution , as follows:
1. Remove phone from PC and remove battery to shut off phone.
2. Plug USB cable into PC.
3. Plug USB cable (other end) into phone.
4. The PC install new hardware appropriate drivers for a few minutes (phone without battery)
5. Unplug USB cable from phone
6. Put battery back in and turn on phone
7. As the phone boots, hold down Volume up and down. Phone boots into safe mode.
8. Plug USB cable into phone.
9. I saw notification about USB MTP-connecting on the phone. PC have found my phone!
10. After the reboot in normal mode problem was fixed
