Making of backups can save your life. In many cases the process of recovering lost funds is easier and possible with an old backup. The important thing is the wallet files should to be “untouched”, so every operation, attempt to open the wallet should be done using the “copy” of the wallet files not the orginal. Newer versions of Wallets can convert and upgrade the wallet files to new standards and sometimes destroy their structure and make then unrecoverable. This may happen with old backups when the wallet files may be corrupt, damaged, interrupted or come from the bugged version of wallet application. During the years of research we have developed many useful tools to scan, fix and repair such wallet files. You need to remember: LEAVE THE COPY OF THE WALLET UNTOUCHED, otherwise you man loose your funds forever. Many wallets generate new private key and address while new transaction is generated but do not worry, they can still be recovered from and old backup.
How to find wallet files to make backup
The wallet files like wallet.dat in bitcoin core wallet (litecoin, doge, digibyte, darkcoin “dash” and many more coins) you can find here:
WindowsC:\Users\YourUserName\Appdata\Roaming\Bitcoin (Vista,7,8,10)
Mac
~/Library/Application Support/Bitcoin/
Linux/Unix
~/.bitcoin/
Multibit and Multibit HD
All the files under these directories should be zipped and backup
Windows locations:
C:\Users\YourUserName\AppData\Roaming\MultiBit\
C:\Users\YourUserName\AppData\Roaming\MultiBitHD\
Mac locations:
/Users/YourUserName/Library/Application Data/MultiBit/
/Users/YourUserName/Library/Application Support/MultiBit/
Electrum like wallets
WIndows locations:
C:\Users\YourUserName\AppData\Roaming\Electrum\wallets\
file names examples: multibit.key, multibit.wallet, wallet.aes
