This can be really painfull – you made you translation and at compiling time you see such error:

Localizable.strings:0: error: validation failed: The data couldn’t be read because it has been corrupted.

Don’t worry, you dont need to manually check it line by line, just open Terminal, go to folder with your Localizable.strings and enter:

plutil -lint Localizable.strings

you will see output like this:

2014-06-14 15:28:03.516 plutil[855:507] CFPropertyListCreateFromXMLData(): Old-style plist parser: missing semicolon in dictionary on line 68. Parsing will be abandoned. Break on _CFPropertyListMissingSemicolon to debug.
 Localizable.strings: Unexpected character / at line 1

which gives you exact line number and reason.