---
title: Safe Mode
---

Deephaven's Safe Mode feature allows users to log into the Deephaven Web UI without the `WebClientData` Persistent Query (PQ) running. When `WebClientData` is down or unavailable, normal login is not possible. Safe Mode enables logging into Deephaven to troubleshoot the issue.

To use Safe Mode, click the cog icon to show the Login Options and enter your user credentials, then check the **Safe Mode** checkbox and click **Login**.

![The Deephaven login screen](../../assets/safe-mode/login.png)

The Safe Mode screen consists of two sections: the Query Summary and the Console.

![The Safe Mode screen](../../assets/safe-mode/main.png)

On the Query Summary panel, you can select a Persistent Query to view its details and status, or start and stop the query using the corresponding buttons next to the query selection dropdown. The `WebClientData` query is selected by default upon Safe Mode login.

The Query Editor tab allows you to edit and save a query's settings. Use this to fix issues with `WebClientData`, such as increasing heap size or adding debugging flags. You can also disable problematic queries from this editor.

The Console allows users to run commands to troubleshoot the queries. See [Monitor query performance](../../performance/monitor-queries.md) for more details.

> [!NOTE]
> Safe Mode command history is stored in the local storage in the browser and is separate from the regular command history.

To reset your current workspace, use the **Reset Workspace** button. This clears your workspace data in the `WebClientData` PQ, allowing you to start fresh with the default settings. This button only clears _your_ current workspace, so other workspaces, dashboards, and queries are unaffected.

## Related documentation

- [Console](./code-studio.md#console)
- [Monitor query performance](../../performance/monitor-queries.md)