For some users, unrooting is required when the phone has to go back to the manufacturer for repair. If the handset develops a warranty fault (a crackling speaker, non-working camera and so on) it’s likely that the manufacturer will refuse to fix it under warranty if it can see that a custom ROM
has been installed.
In order for a warranty claim to take place the phone will need to be returned to stock condition. Rooting isn’t illegal as the phone is yours to do what you want with, but most manufacturers won’t fix devices that are hacked as rooting can cause the phone to be unstable and therefore open it up to problems the manufacturer doesn’t cover.
Alternatively, should you ever decide to sell off your rooted phone it may be easier to do if it is set to its default state. Custom ROMs aren’t for everyone and a less technically skilled user may feel more comfortable with a standard feature set.
Unrooting can be a complex procedure with each model requiring a different approach. Here’s how we did it on our HTC Desire test model. If you own a different Android device we urge you to research the necessary steps beforehand.
Discover how to unroot your Android phone
Source : Android Tips, Tricks, Apps and Hacks