+ (NSString*) errorReport:(NSError*) error

ErrorReport.m

+ (NSString*) errorReport:(NSError*) error
{
    NSMutableString* report = [NSMutableString new];
    [report appendString:[NSString stringWithFormat:@"%@: %li\n\n%@", error.domain, error.code, error.userInfo]];
    if( error = [[error userInfo] objectForKey:NSUnderlyingErrorKey] ) // we have to go deeper
    {
        [report appendString:[NSString stringWithFormat:@"\n\n- Underlying Error -\n\n"]];
        [report appendString:[self errorReport:error]];
    }
    return report;
}