diff --git a/internal/database/db.go b/internal/database/db.go
index b82294add..2e5c99f83 100644
--- a/internal/database/db.go
+++ b/internal/database/db.go
@@ -2698,6 +2698,11 @@ func InitDB(dbPath string) error {
 	}
 	c := &gorm.Config{Logger: gormLogger, DisableForeignKeyConstraintWhenMigrating: true}
 
+	// Reopening replaces the process pool; the replaced one would keep its file open.
+	if err := CloseDB(); err != nil {
+		log.Printf("close the replaced database pool: %v", err)
+	}
+
 	var err error
 	switch config.GetDBKind() {
 	case "postgres":
diff --git a/internal/database/db_reopen_test.go b/internal/database/db_reopen_test.go
new file mode 100644
index 000000000..c3c856161
--- /dev/null
+++ b/internal/database/db_reopen_test.go
@@ -0,0 +1,27 @@
+package database
+
+import (
+	"path/filepath"
+	"testing"
+)
+
+// A replaced pool that stays open keeps its database file open; Windows then
+// cannot delete or replace that file.
+func TestInitDBClosesThePoolItReplaces(t *testing.T) {
+	dbPath := filepath.Join(t.TempDir(), "x-ui.db")
+	if err := InitDB(dbPath); err != nil {
+		t.Fatalf("first InitDB: %v", err)
+	}
+	t.Cleanup(func() { _ = CloseDB() })
+	replaced, err := GetDB().DB()
+	if err != nil {
+		t.Fatalf("first pool: %v", err)
+	}
+
+	if err := InitDB(dbPath); err != nil {
+		t.Fatalf("second InitDB: %v", err)
+	}
+	if err := replaced.Ping(); err == nil || err.Error() != "sql: database is closed" {
+		t.Fatalf("replaced pool Ping() = %v, want sql: database is closed", err)
+	}
+}