diff --git a/cmd/backups/restore.go b/cmd/backups/restore.go
index b6117b1..8a100b6 100644
--- a/cmd/backups/restore.go
+++ b/cmd/backups/restore.go
@@ -23,6 +23,33 @@ func RestoreCmd() *cobra.Command {
 		RunE: func(cmd *cobra.Command, args []string) error {
 			ui.NewlineAbove()
 
+			db, err := storage.Initialize()
+			if err != nil {
+				ui.PrintError(ui.EmojiError, fmt.Sprintf("%v", err))
+				ui.NewlineBelow()
+				return ui.ErrHandled
+			}
+
+			running, err := db.GetRunningEntry()
+			if err != nil {
+				db.Close()
+				ui.PrintError(ui.EmojiError, fmt.Sprintf("checking for active timer: %v", err))
+				ui.NewlineBelow()
+				return ui.ErrHandled
+			}
+			if running != nil {
+				db.Close()
+				ui.PrintError(ui.EmojiError, fmt.Sprintf(`timer is running for %s — stop it before restoring a backup`, ui.Bold(running.ProjectName)))
+				ui.NewlineBelow()
+				return ui.ErrHandled
+			}
+
+			if err := db.Close(); err != nil {
+				ui.PrintError(ui.EmojiError, fmt.Sprintf("closing database: %v", err))
+				ui.NewlineBelow()
+				return ui.ErrHandled
+			}
+
 			backups, err := storage.ListBackups()
 			if err != nil {
 				ui.PrintError(ui.EmojiError, fmt.Sprintf("listing backups: %v", err))
diff --git a/cmd/backups/restore_test.go b/cmd/backups/restore_test.go
new file mode 100644
index 0000000..87d0e97
--- /dev/null
+++ b/cmd/backups/restore_test.go
@@ -0,0 +1,89 @@
+package backups
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/DylanDevelops/tmpo/internal/storage"
+	"github.com/DylanDevelops/tmpo/internal/ui"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// setupBackupTestHome points the storage layer at an isolated temp home so
+// tests never touch the real ~/.tmpo directory.
+func setupBackupTestHome(t *testing.T) {
+	t.Helper()
+	tmpHome := t.TempDir()
+	t.Setenv("HOME", tmpHome)
+	t.Setenv("USERPROFILE", tmpHome)
+	t.Setenv("TMPO_DEV", "1")
+}
+
+// TestRestoreCmd_BlocksWhenTimerRunning verifies the guard added for issue #134:
+// a restore must refuse while a timer is running instead of silently
+// obliterating the in-flight entry.
+func TestRestoreCmd_BlocksWhenTimerRunning(t *testing.T) {
+	setupBackupTestHome(t)
+
+	// Start a running timer, then take a backup so a restore target exists.
+	db, err := storage.Initialize()
+	require.NoError(t, err)
+	_, err = db.CreateEntry("proj", "in flight", nil, nil)
+	require.NoError(t, err)
+	_, err = db.CreateBackup()
+	require.NoError(t, err)
+	require.NoError(t, db.Close())
+
+	cmd := RestoreCmd()
+	err = cmd.RunE(cmd, []string{})
+
+	// The command must report a handled failure and stop before any restore.
+	assert.True(t, errors.Is(err, ui.ErrHandled), "expected ui.ErrHandled, got %v", err)
+
+	// The running entry must survive untouched.
+	db2, err := storage.Initialize()
+	require.NoError(t, err)
+	defer db2.Close()
+	running, err := db2.GetRunningEntry()
+	require.NoError(t, err)
+	require.NotNil(t, running, "running timer should not have been destroyed")
+	assert.Equal(t, "in flight", running.Description)
+}
+
+// TestRestoreCmd_NoTimerNoBackups confirms the guard passes cleanly when no
+// timer is running: with no backups present the command exits without error.
+func TestRestoreCmd_NoTimerNoBackups(t *testing.T) {
+	setupBackupTestHome(t)
+
+	// Initialize the DB (no running timer, no backups created).
+	db, err := storage.Initialize()
+	require.NoError(t, err)
+	require.NoError(t, db.Close())
+
+	cmd := RestoreCmd()
+	err = cmd.RunE(cmd, []string{})
+
+	// No timer and no backups is a clean no-op, not a failure.
+	assert.NoError(t, err)
+}
+
+// TestRestoreCmd_NoTimerInvalidID confirms that once the guard passes, the
+// --id lookup still runs and reports a handled error for an unknown ID.
+func TestRestoreCmd_NoTimerInvalidID(t *testing.T) {
+	setupBackupTestHome(t)
+
+	// A backup must exist so the command reaches the ID lookup rather than the
+	// "no backups found" early return.
+	db, err := storage.Initialize()
+	require.NoError(t, err)
+	_, err = db.CreateBackup()
+	require.NoError(t, err)
+	require.NoError(t, db.Close())
+
+	cmd := RestoreCmd()
+	require.NoError(t, cmd.Flags().Set("id", "9999"))
+	err = cmd.RunE(cmd, []string{})
+
+	assert.True(t, errors.Is(err, ui.ErrHandled), "expected ui.ErrHandled, got %v", err)
+}
diff --git a/internal/storage/backup.go b/internal/storage/backup.go
index aa02112..0e81db1 100644
--- a/internal/storage/backup.go
+++ b/internal/storage/backup.go
@@ -146,6 +146,12 @@ func RestoreBackup(backupPath string) error {
 	}
 	defer src.Close()
 
+	for _, suffix := range []string{"-journal", "-wal", "-shm"} {
+		if err := os.Remove(dbPath + suffix); err != nil && !os.IsNotExist(err) {
+			return fmt.Errorf("failed to remove stale %s file: %w", suffix, err)
+		}
+	}
+
 	dst, err := os.Create(dbPath)
 	if err != nil {
 		return fmt.Errorf("failed to open database for writing: %w", err)
diff --git a/internal/storage/backup_test.go b/internal/storage/backup_test.go
index bf4b221..a49f9dc 100644
--- a/internal/storage/backup_test.go
+++ b/internal/storage/backup_test.go
@@ -260,6 +260,74 @@ func TestRestoreBackup(t *testing.T) {
 	assert.Equal(t, "before backup", entries[0].Description)
 }
 
+func TestRestoreBackup_RemovesStaleWALSidecars(t *testing.T) {
+	tmpHome := t.TempDir()
+	t.Setenv("HOME", tmpHome)
+	t.Setenv("USERPROFILE", tmpHome)
+	t.Setenv("TMPO_DEV", "")
+
+	// Create and populate the live DB, then snapshot it
+	db, err := Initialize()
+	assert.NoError(t, err)
+	_, err = db.CreateEntry("test-project", "before backup", nil, nil)
+	assert.NoError(t, err)
+
+	backup, err := db.CreateBackup()
+	assert.NoError(t, err)
+	db.Close()
+
+	// Simulate leftover sidecar files next to the live DB. tmpo runs in the
+	// default (rollback) journal mode, so -journal is the sidecar that can
+	// actually occur; -wal/-shm are covered defensively.
+	dbPath, err := GetDBPath()
+	assert.NoError(t, err)
+	journalPath := dbPath + "-journal"
+	walPath := dbPath + "-wal"
+	shmPath := dbPath + "-shm"
+	assert.NoError(t, os.WriteFile(journalPath, []byte("stale journal"), 0600))
+	assert.NoError(t, os.WriteFile(walPath, []byte("stale wal"), 0600))
+	assert.NoError(t, os.WriteFile(shmPath, []byte("stale shm"), 0600))
+
+	// Restore should clear the stale sidecars so they cannot shadow the DB
+	assert.NoError(t, RestoreBackup(backup.Path))
+
+	_, err = os.Stat(journalPath)
+	assert.True(t, os.IsNotExist(err), "expected stale -journal file to be removed")
+	_, err = os.Stat(walPath)
+	assert.True(t, os.IsNotExist(err), "expected stale -wal file to be removed")
+	_, err = os.Stat(shmPath)
+	assert.True(t, os.IsNotExist(err), "expected stale -shm file to be removed")
+
+	// Restored data must still be intact
+	db2, err := Initialize()
+	assert.NoError(t, err)
+	defer db2.Close()
+
+	entries, err := db2.GetEntries(0)
+	assert.NoError(t, err)
+	assert.Len(t, entries, 1)
+	assert.Equal(t, "before backup", entries[0].Description)
+}
+
+func TestRestoreBackup_SucceedsWithoutSidecars(t *testing.T) {
+	tmpHome := t.TempDir()
+	t.Setenv("HOME", tmpHome)
+	t.Setenv("USERPROFILE", tmpHome)
+	t.Setenv("TMPO_DEV", "")
+
+	db, err := Initialize()
+	assert.NoError(t, err)
+	_, err = db.CreateEntry("test-project", "before backup", nil, nil)
+	assert.NoError(t, err)
+
+	backup, err := db.CreateBackup()
+	assert.NoError(t, err)
+	db.Close()
+
+	// No sidecar files exist; restore must still succeed cleanly
+	assert.NoError(t, RestoreBackup(backup.Path))
+}
+
 func TestCreateBackup_SetsPrivatePermissions(t *testing.T) {
 	if runtime.GOOS == "windows" {
 		t.Skip("POSIX permissions are not enforced on Windows")
diff --git a/internal/storage/db.go b/internal/storage/db.go
index 2e61def..ffb105b 100644
--- a/internal/storage/db.go
+++ b/internal/storage/db.go
@@ -108,7 +108,7 @@ func Initialize() (*Database, error) {
 	if err := fsperm.SecureFile(dbPath); err != nil {
 		return nil, err
 	}
-	for _, suffix := range []string{"-wal", "-shm"} {
+	for _, suffix := range []string{"-journal", "-wal", "-shm"} {
 		if err := fsperm.SecureFile(dbPath + suffix); err != nil {
 			return nil, err
 		}