diff --git a/CHANGELOG.md b/CHANGELOG.md
index a4c57a4..1f84f74 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -23,6 +23,7 @@ The format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/), and
 - Badges and search results use simple line icons instead of emoji.
 
 ### Fixed
+- Importing a backup with a 0-minute session no longer turns it into 30 minutes; zero and negative durations are clamped to 1, the same as any other out-of-range value.
 - Finished goals no longer show as "late".
 - The chosen profile picture in Settings is now visibly selected.
 - Search results can be opened with the keyboard.
diff --git a/assets/js/storage.js b/assets/js/storage.js
index 7ec53be..c27073c 100644
--- a/assets/js/storage.js
+++ b/assets/js/storage.js
@@ -684,7 +684,8 @@ class StorageManager {
         g.progress = Math.min(100, Math.max(0, parseInt(g.progress, 10) || 0));
       });
       parsed.activities.forEach(a => {
-        a.duration = Math.max(1, parseInt(a.duration, 10) || 30);
+        const duration = parseInt(a.duration, 10);
+        a.duration = Math.max(1, Number.isNaN(duration) ? 30 : duration);
       });
 
       this.saveUniverse(parsed);
diff --git a/tests/storage.test.js b/tests/storage.test.js
index 7157511..d38d4dc 100644
--- a/tests/storage.test.js
+++ b/tests/storage.test.js
@@ -174,9 +174,13 @@ describe('import and export', () => {
           { id: 's2', progress: -5 }
         ],
         projects: [{ id: 'p1', progress: '42' }],
+        // Every activity needs a valid date: imports drop dateless entries
+        // (see the malformed-dates security test below).
         activities: [
-          { id: 'a1', duration: -10 },
-          { id: 'a2', duration: 'x' }
+          { id: 'a1', date: '2026-11-01', duration: -10 },
+          { id: 'a2', date: '2026-11-02', duration: 'x' },
+          { id: 'a3', date: '2026-11-03', duration: 0 },
+          { id: 'a4', date: '2026-11-04' }
         ]
       })
     );
@@ -188,6 +192,11 @@ describe('import and export', () => {
     assert.equal(u.projects[0].progress, 42);
     assert.deepEqual(u.projects[0].technologies, []);
     for (const a of u.activities) assert.ok(a.duration >= 1, `duration ${a.duration}`);
+    // -10 -> 1 (minimum), 0 -> 1, non-numeric/missing -> 30 (default)
+    assert.deepEqual(
+      u.activities.map(a => a.duration),
+      [1, 30, 1, 30]
+    );
   });
 
   // Regression for D-009: a backup without a profile used to become "Alex Rivera".