I copied my wallet to another computer, then generate a new address, and received some coins with the new address, the balance added. But I can't see any change in my original computer and balance. Why? Doesn't the wallet recognise the new address generated by its copy?
Thank you for any help.
The wallet only knows what's in it. If you copied the wallet and it did not have the new address yet, your new address was created on your new wallet. To get it on the other PC you have to re-copy your latest copy of the wallet and move it back there.
Wallet files do not sync with each other -- this is why it's so important to back up often.