Multiple critical issues on Windows 11 (v1.24b): YouTube playback stutter/skip, performance freezes, and complete data loss via sync #16322

Preliminary Checks

• I have read and understood the important section above.
• I have searched existing issues and avoided creating duplicates.
• I am not filing an enhancement request.
• I have checked that this issue cannot be reproduced on Mozilla Firefox.
• I have checked that this issue can be reproduced once I removed all my Mods and Custom CSS.

What happened?

What happened?

I’m experiencing several serious issues with Zen Browser on Windows 11, version 1.24b (64-bit), and I’d like to report them in detail.

1. Video playback issues on streaming sites (e.g., YouTube)
   Video playback randomly stops or stutters. In playlists, the browser literally skips the current song/video and selects a random one from the list on its own. When playback stops, a “loading” icon appears as if there’s no internet connection. I initially thought this was an internet issue and even called my ISP for support, but the problem persisted. As soon as I switched to a different browser, the issue completely disappeared.

2. Performance problems
   I stream with the browser open, and several applications frequently freeze or become unresponsive while Zen is running. This doesn’t happen with Vivaldi, which I’m now considering switching to — even though Zen is still my favorite browser. No other browser matches Zen’s productivity features and fluidity, or the trust of a long-standing daily driver (for example, Dia doesn’t even have a Spanish interface, and Arc is no longer being updated).

3. Critical data loss via sync
   This is the most serious issue. I had browser sync enabled (I understand Zen uses cloud sync). I had to format my PC for maintenance reasons, and when I logged back in, all my data was gone — no bookmarks, no passwords, nothing. This was very frustrating, as I’ve been using this browser for a long time and genuinely love what the team is building. Even my session on my phone got reset after logging in again on the PC, and in the end I lost all my data permanently.

4. Camera/microphone permission bugs
   When a site requests camera or microphone access, the permission prompt sometimes doesn’t appear at all, or the camera simply never loads/initializes even after granting access.

I’m filing this report because I really like this browser and want to see these issues fixed. Happy to provide more details, logs, or reproduction steps if needed.

Expected behavior

Video and audio playback on streaming sites (YouTube, etc.) should play smoothly without random stuttering, stopping, or buffering, and playlists should not skip or shuffle to a different track/video on their own. The browser should run efficiently in the background without causing other applications to freeze or become unresponsive, even during extended use (e.g., while streaming). Sync should reliably preserve bookmarks, passwords, and other user data across devices and after a system reinstall/format — a sync feature should never result in permanent data loss on all synced devices. Camera and microphone permission prompts should always appear when a site requests access, and once granted, the camera/microphone should initialize and work correctly without failing to load.

Actual behavior

Instead of the expected behavior described above, the following occurs: Video/audio playback on YouTube and other streaming sites frequently stutters, stops, or shows a buffering/loading icon despite a stable internet connection. In playlists, the browser skips the current video and jumps to a random one instead of continuing in order. While streaming with Zen Browser open, other applications on the system frequently freeze or become unresponsive, which does not happen when using Vivaldi under the same conditions. After enabling sync, formatting the PC, and logging back into the same Zen Account, all synced data (bookmarks, passwords) was permanently lost. The sync session on a mobile device was also reset/logged out after logging into the PC again, resulting in total data loss across devices. Camera/microphone permission prompts sometimes fail to appear when a site requests access, and even after granting permission, the camera does not initialize or load.

Steps to reproduce

Steps to reproduce

Issue 1 — Video playback (YouTube / streaming sites):

Open Zen Browser and go to YouTube.
Start playing a video or a playlist.
Let it play for a while (issue occurs intermittently, not on a fixed timer).
Observe that playback randomly stops, shows the buffering/loading icon (even with a stable internet connection), or skips to a random track/video in the playlist instead of continuing in order.
For comparison: open the same video/playlist in another browser (e.g., Vivaldi) — the issue does not occur.

Issue 2 — Performance / app freezing:

Open Zen Browser with multiple tabs.
Start a stream (e.g., using OBS or another streaming app) while the browser remains open.
Continue using the PC normally during the stream.
Observe that other open applications frequently freeze or become unresponsive while Zen is running in the background.
For comparison: repeat the same workflow with Vivaldi open instead — the freezing does not occur.

Issue 3 — Data loss via sync:

Enable Zen Account sync (bookmarks, passwords, etc.) on a PC and, optionally, on a mobile device.
Format/reinstall Windows 11 on the PC for maintenance purposes.
Reinstall Zen Browser and log back into the same Zen Account.
Observe that no synced data (bookmarks, passwords, etc.) is restored.
Check the mobile device’s session — observe that it has also been reset/logged out, and the previously synced data is lost there as well.

Issue 4 — Camera/microphone permissions:

Visit a site that requests camera and/or microphone access (e.g., a video call service).
Trigger the permission prompt by starting a call or clicking “allow camera/microphone.”
Observe that the permission prompt sometimes does not appear at all, or appears but the camera never initializes/loads even after access is granted.

Screenshots and videos

No response

Version

Versión 1.24b (64-bit

What platform are you seeing the problem on?

Windows - x64

What component is this issue related to?

Performance

Relevant log output if applicable