The error you are getting is typically related to Android devices detaching their SD card storage. When your app is built with LiveSync ON (aka in Debug mode), the package is unpacked on the SD card, and all changes are refreshed there. If Android cannot find the SD card, it cannot load the contents of your app and your app will crash with the reported error message.
When you're getting this error, is your device connected to your computer? If yes, try playing around with the USB connection type/mode of your device - try switching between Media storage and any other options you have there. Explore your device options and look for anything that might be detaching your SD card.
Another thing you can do is build your app in Release mode
. This will not require your app being unpacked on the SD card and you will be able to run your app.
Let us know if your data transfer issues still occur afterwards.
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