Quick Post this time.
For all you googling Unknown error by ErrorCallback in your Samsung Galaxy s3.
I have a bad news for you.
It is a hardware problem.
Forget wiping cache, don’t bother with factory reset. Sure you can try the famous solution of tapping the camera as you open the Camera App, it works well for many people but this just proves my point that it is a hardware issue if you must tap it to make it work.
Two solutions to fix it:
1. Clean the connector
If you are lucky, it’s only the dirt on the connector/socket of the camera unit. You still must dissassemble the phone to access the camera unit.
2. Replace the whole camera unit.
That’s what I had to do in my case. Easy job. 10$ from eBay, replaced in 5 minutes.
Don’t waste your time, just replace it to make the Unknown Error by ErrorCallback go away from your Samsung Galaxy S3 for ever.
Hope it helps.