Q: When my car and my Samsung Galaxy S5 phone connect via Bluetooth, the phone's notification alert tone goes off every 15 seconds. But when I check the phone, there are no notification messages. What can I do?
Dave Elgethun, Eden Prairie
A: The problem is probably a misbehaving app or an error in the phone's sound software. Try these methods to fix it:
• See if the problem lies with an app. One method is to click Apps, then Settings and then "Notifications." You will see a list of your phone's apps, each with an on-off switch. Turn them off one at a time to see if the unwanted tone goes away.
Another method is to put the phone in "safe mode" (see tinyurl.com/1loueefc). If the problem disappears in safe mode, then an app that you have added to the phone is at fault. You will need to uninstall your acquired apps one at a time to find the culprit.
• See if the problem is caused by the phone's sound software. Click Apps, then Settings, then "Sounds and vibration." Turn off these options one by one to see if the recurring tone disappears: "Touch sounds" (caused by touching the screen), "Screen lock sounds," "Emergency tone" and "Charging sound" (caused by attaching a charger).
• If neither approach works, try deleting the data files in the phone's "cache partition" (see tinyurl.com/xmjg8xd6). These temporary files may have been corrupted during an app installation or a phone software update. Erasing them won't affect your personal phone data.
• As a last resort, do a "factory reset" on the phone (see tinyurl.com/1jxlg4h4), which returns it to its original settings and content. This reset will delete your personal data, so back it up first.
