I own a Samsung Galaxy S3 mini android phone. Recently, within the last 2 days (as from 2 June, 2017), the phone started to make a strange knocking noise at irregular intervals. N.B. the noise is not accompanied by anything else, such as a pop-up message.
I have let a Norton technical support person look at the phone and he has confirmed that the phone is not infected by a virus, but this does not explain why the noise is being made.
When the phone was scanned with Norton Mobile, it did 91% of the scan very quickly, within 30 minutes, but then took a long time - up to a few hours - to scan the SD card.. This last part of the scan never completes.
Is this a problem with a corrupted SD card that a virus has attacked (for example)?
What actions should I take? Replace the SD card or what?