diff --git a/src/bin/rebuild-db.rs b/src/bin/rebuild-db.rs
new file mode 100644
index 0000000..1906213
--- /dev/null
+++ b/src/bin/rebuild-db.rs
@@ -0,0 +1,29 @@
+use std::env;
+
+use inboxid::*;
+use itertools::Itertools;
+use mailparse::MailHeaderMap;
+use rusqlite::params;
+
+fn main() -> Result<()> {
+	let db = get_db()?;
+	let mut delete_mail = db.prepare("DELETE FROM mail WHERE mailbox = ?")?;
+	let mut save_mail = db.prepare("INSERT INTO mail VALUES (?,?,?)")?;
+	let mailboxes = env::args().skip(1).collect_vec();
+	for mailbox in mailboxes {
+		let maildir = get_maildir(&mailbox)?;
+		delete_mail.execute(params![&mailbox])?;
+		let mut mails = Vec::new();
+		for x in maildir.list_cur() {
+			mails.push(x?);
+		}
+		let mut mails = maildir.get_mails(&mut mails)?;
+		mails.sort_by_key(|x| x.date);
+		for mail in mails {
+			let headers = mail.get_headers();
+			let message_id = headers.get_all_values("Message-ID").join(" ");
+			save_mail.execute(params![&mailbox, mail.id.to_i64(), message_id])?;
+		}
+	}
+	Ok(())
+}
diff --git a/src/bin/sync.rs b/src/bin/sync.rs
index e7f650f..e41c16e 100644
--- a/src/bin/sync.rs
+++ b/src/bin/sync.rs
@@ -82,14 +82,15 @@ fn sync(
 				let local_uid1 = (full_uid >> 32) as u32;
 				let local_uid2 = ((full_uid << 32) >> 32) as u32;
 				let local_id = gen_id(local_uid1, local_uid2);
+				let new_uid = MaildirID::new(uid1, uid2);
+				let new_id = new_uid.to_string();
 				// hardlink mail
 				let maildir1 = &maildirs[&**inbox];
+				println!("hardlinking: {}/{} -> {}/{}", inbox, local_id, mailbox, new_id);
 				let name = maildir1.find_filename(&local_id).unwrap();
 				let maildir2 = &maildirs[mailbox];
-				let new_id = gen_id(uid1, uid2);
-				println!("hardlinking: {}/{} -> {}/{}", inbox, local_id, mailbox, new_id);
 				maildir2.store_cur_from_path(&new_id, name)?;
-				save_mail.execute(params![mailbox, store_i64(*full_uid), message_id])?;
+				save_mail.execute(params![mailbox, new_uid.to_i64(), message_id])?;
 			} else {
 				to_fetch.push(uid2);
 			}
diff --git a/src/lib.rs b/src/lib.rs
index 1ed270e..5c363e8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -78,6 +78,19 @@ impl ToString for MaildirID {
 	}
 }
 
+impl MaildirID {
+	pub fn new(x: u32, y: u32) -> Self {
+		Self {
+			uid_validity: x,
+			uid: y
+		}
+	}
+
+	pub fn to_i64(&self) -> i64 {
+		store_i64(((self.uid_validity as u64) << 32) | self.uid as u64)
+	}
+}
+
 pub struct EasyMail<'a> {
 	pub mail: ParsedMail<'a>,
 	pub id: MaildirID,