diff --git a/src/domain/mbox/arg.rs b/src/domain/mbox/arg.rs
index bfa4e0db..5d58f0f4 100644
--- a/src/domain/mbox/arg.rs
+++ b/src/domain/mbox/arg.rs
@@ -44,4 +44,5 @@ pub fn target_arg<'a>() -> Arg<'a, 'a> {
     Arg::with_name("target")
         .help("Specifies the targetted mailbox")
         .value_name("TARGET")
+        .required(true)
 }
diff --git a/src/domain/mbox/entity.rs b/src/domain/mbox/entity.rs
index 1541a164..0b9550f1 100644
--- a/src/domain/mbox/entity.rs
+++ b/src/domain/mbox/entity.rs
@@ -152,7 +152,9 @@ impl TryFrom<Option<&str>> for Mbox {
     fn try_from(mbox: Option<&str>) -> Result<Self, Self::Error> {
         debug!("init mailbox from `{:?}`", mbox);
         Ok(Self {
-            name: mbox.ok_or(anyhow!("cannot parse mailbox"))?.to_string(),
+            name: mbox
+                .ok_or(anyhow!("the target mailbox cannot be empty"))?
+                .to_string(),
             ..Self::default()
         })
     }
diff --git a/src/domain/msg/arg.rs b/src/domain/msg/arg.rs
index 40da564c..6412e289 100644
--- a/src/domain/msg/arg.rs
+++ b/src/domain/msg/arg.rs
@@ -288,7 +288,7 @@ pub fn subcmds<'a>() -> Vec<App<'a, 'a>> {
                 .arg(uid_arg())
                 .arg(msg::attachment::arg::path_arg()),
             SubCommand::with_name("copy")
-                .aliases(&["cp"])
+                .aliases(&["cp", "c"])
                 .about("Copies a message to the targetted mailbox")
                 .arg(uid_arg())
                 .arg(mbox::arg::target_arg()),
diff --git a/src/domain/msg/handler.rs b/src/domain/msg/handler.rs
index d74404ad..61d6c4c9 100644
--- a/src/domain/msg/handler.rs
+++ b/src/domain/msg/handler.rs
@@ -149,7 +149,8 @@ pub fn attachments<OutputService: OutputServiceInterface, ImapService: ImapServi
     Ok(())
 }
 
-pub fn copy<ImapService: ImapServiceInterface>(
+/// Copy the given message UID to the targetted mailbox.
+pub fn copy<OutputService: OutputServiceInterface, ImapService: ImapServiceInterface>(
     uid: &str,
     mbox: Option<&str>,
     output: &OutputService,
@@ -157,12 +158,10 @@ pub fn copy<ImapService: ImapServiceInterface>(
 ) -> Result<()> {
     let target = Mbox::try_from(mbox)?;
     let mut msg = imap.get_msg(&uid)?;
-    // the message, which will be in the new mailbox doesn't need to be seen
     msg.flags.insert(Flag::Seen);
     imap.append_msg(&target, &mut msg)?;
-    debug!("message {} successfully copied to folder `{}`", uid, target);
     output.print(format!(
-        "Message {} successfully copied to folder `{}`",
+        r#"Message {} successfully copied to folder "{}""#,
         uid, target
     ))?;
     imap.logout()?;