Usually, when a flash drive asks to be formated, it's because it was damaged or the files have been corrupted.
Anyway I think that your only hope is this one as USB Fix does fix many issues:
# Download USB Fix click here
- Launch it, a shortcut will be created on your desktop.
- Choose "Clean" option.
- A pop-up will follow Connect all your external data sources to your PC (Usb keys, sd cards external drives, etc...)
- Once you're ready, click "OK".
- While cleaning, you will lose access to your desktop, but this is normal.
Tutorial : http://www.en.usbfix.net/2014/02/usbfix-tutorial-clean-option/
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