diff --git a/worker/imap/seqmap.go b/worker/imap/seqmap.go
index 3558fe4..4a84586 100644
--- a/worker/imap/seqmap.go
+++ b/worker/imap/seqmap.go
@@ -14,7 +14,8 @@ type SeqMap struct {
 // Initialize sets the initial seqmap of the mailbox
 func (s *SeqMap) Initialize(uids []uint32) {
 	s.lock.Lock()
-	s.m = uids
+	s.m = make([]uint32, len(uids))
+	copy(s.m, uids)
 	s.sort()
 	s.lock.Unlock()
 }
diff --git a/worker/imap/seqmap_test.go b/worker/imap/seqmap_test.go
index 42c06f8..5d6cf79 100644
--- a/worker/imap/seqmap_test.go
+++ b/worker/imap/seqmap_test.go
@@ -22,8 +22,11 @@ func TestSeqMap(t *testing.T) {
 	_, found = seqmap.Pop(0)
 	assert.Equal(false, found)
 
-	seqmap.Initialize([]uint32{1337, 42, 1107})
+	uids := []uint32{1337, 42, 1107}
+	seqmap.Initialize(uids)
 	assert.Equal(3, seqmap.Size())
+	// Original list should remain unsorted
+	assert.Equal([]uint32{1337, 42, 1107}, uids)
 
 	_, found = seqmap.Pop(0)
 	assert.Equal(false, found)