I can understand why the phone cannot access these files while it is plugged in, as the SD card is not accessible to the phone at all at that point. Really, this is a bit of stupidity on Android's part. The only other solution is to never plug my phone into the computer again. This way, my custom settings won't be either. The stock notifications are never disturbed. I'm hoping to find the location of the internal storage where the stock ring tones and notification sounds are kept so that I can put my custom ring tones and notifications there.
Since the phone cannot find the associated ringtone or notification sound, it just randomly assigns another and does not switch it back once the phone is unplugged. What happens is that the ringtones and notifications for email, SMS, and any other app that stores these files on the SD card cannot find them once the phone is plugged into a computer via USB if the phone is set to allow direct access via the computer. I found out it happened every time I plugged the phone into my computer via a USB cable. I discovered the source of a problem wherein my phone would seemingly randomly change my notifications. Where are these files stored on the internal phone storage? I'm not talking about the SD card.