# DR Sim Manager Won't Start Anymore

If DR Sim Manager won't launch, crashes on startup, or shows an error dialog before opening, this guide covers the most common causes and fixes.

***

## Quick Fixes (Try These First)

### Reset the UI Configuration

The most common cause of startup failures is a corrupted UI configuration file. To reset it:

1. Navigate to `C:\Users\<UserName>\AppData\Local\DRSimManager`.
2. Delete the `ui.config` file.
3. Try to relaunch DR Sim Manager.

This resets window positions, dock layouts, and UI state without affecting your profiles, outputs, or license.

### Reset All Configuration

If deleting `ui.config` alone doesn't help, delete all configuration files to start fresh:

1. Navigate to `C:\Users\<UserName>\AppData\Local\DRSimManager`.
2. Delete the following files: `app.json`, `sim.json`, `outputs.json`, and `ui.config`.
3. Try to relaunch DR Sim Manager.

Your **Profiles** and **license** are preserved — only application settings are reset to defaults.

<figure><img src="/files/NDu3t1IWxCYblVpDtbof" alt=""><figcaption></figcaption></figure>

{% hint style="warning" %}
Deleting configuration files resets all your settings (refresh rate, safety thresholds, gains, etc.) to defaults. Your profiles, hardware profiles, and license are not affected. Back up the files first if you want to preserve them.
{% endhint %}

***

## Common Causes

### Corrupted Configuration Files

If a configuration file (`app.json`, `sim.json`, `outputs.json`, or `ui.config`) becomes corrupted — for example, due to a power failure during saving or a disk error — DR Sim Manager may fail to start. Symptoms include:

* The application flashes briefly and closes
* An error dialog mentioning configuration or data loading
* The application hangs on the splash screen

**Fix:** Delete the corrupted configuration files as described above.

### Antivirus or Windows Defender Blocking

Some antivirus software may flag DR Sim Manager as suspicious, particularly after an update. This can prevent the application from starting or cause it to crash immediately.

**How to check:**

1. Open **Windows Security** → **Virus & threat protection** → **Protection history**.
2. Look for any recent entries related to DR Sim Manager or DRSimManager.exe.
3. If you find a block, click on it and select **Allow on device**.

**How to add an exclusion:**

1. Open **Windows Security** → **Virus & threat protection** → **Manage settings** (under Virus & threat protection settings).
2. Scroll down to **Exclusions** and click **Add or remove exclusions**.
3. Click **Add an exclusion** → **Folder**.
4. Add the DR Sim Manager installation folder (default: `C:\Program Files\DR Sim Manager\`).
5. Optionally, also add the data folder: `C:\Users\<UserName>\AppData\Local\DRSimManager\`.

{% hint style="info" %}
If you use a third-party antivirus (Norton, Kaspersky, Bitdefender, etc.), you'll need to add exclusions through that software's interface. Consult your antivirus documentation for how to add folder exclusions.
{% endhint %}

### Missing System Files or DLLs

If Windows system files are damaged or missing, DR Sim Manager may fail to start with an error about missing DLLs or components.

**Common missing components:**

* **Visual C++ Redistributable** — DR Sim Manager requires the latest Visual C++ Redistributable. Download and install it from Microsoft's website.
* **Windows Updates** — Ensure your Windows 11 installation is fully up to date.

**How to fix:**

1. Install the latest [Microsoft Visual C++ Redistributable](https://learn.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist).
2. Run **Windows Update** and install all available updates.
3. Try relaunching DR Sim Manager.

### Corrupted License Data

In rare cases, license data corruption can prevent startup. Symptoms include the activation dialog failing to appear or the application crashing during license verification.

**How to fix:**

1. Navigate to `C:\Users\<UserName>\AppData\Local\DRSimManager`.
2. Delete the license file (`drsm.lic`) if it exists.
3. Relaunch DR Sim Manager — the activation dialog will appear.
4. Re-enter your license key and email to reactivate.

### Graphics Driver Issues

DR Sim Manager uses hardware-accelerated rendering for the 3D Sim Visualizer. Outdated or corrupted graphics drivers can cause crashes on startup.

**How to fix:**

1. Update your graphics drivers to the latest version from your GPU manufacturer (NVIDIA, AMD, or Intel).
2. If updating drivers doesn't help, try launching DR Sim Manager with the `-no3d` command line argument (if available) to disable 3D rendering.

***

## How to Check Logs

DR Sim Manager keeps a log file that can help diagnose startup issues:

1. Navigate to `C:\Users\<UserName>\AppData\Local\DRSimManager`.
2. Look for log files named `app_YYYY-MM-DD.log` (e.g., `app_2026-04-19.log`).
3. Open the most recent log file in a text editor.
4. Look for **ERROR** or **CRITICAL** entries near the end of the file — these indicate what went wrong.
5. If you're contacting support, include the log file in your message.

{% hint style="info" %}
The log folder also contains logs from previous days (up to 7 days of logs are kept). If DR Sim Manager crashed yesterday and you're troubleshooting today, check yesterday's log file.
{% endhint %}

### Common Log Error Messages

| Log Message                            | Meaning                                        | Solution                                                       |
| -------------------------------------- | ---------------------------------------------- | -------------------------------------------------------------- |
| "Error" + "configuration"              | A config file is corrupted or has invalid data | Delete the affected config file and relaunch                   |
| "Component Failure" + "failed to load" | A required component couldn't initialize       | Check for missing DLLs or system updates                       |
| "Permission Error"                     | The application can't access a required file   | Check antivirus exclusions; don't run from a restricted folder |
| "A critical system error occurred"     | A low-level crash (access violation, segfault) | Update drivers, check hardware connections                     |
| "An application error occurred"        | An unexpected error during startup             | Check the full log for details; try resetting config           |

***

## Clean Reinstall Procedure

If nothing else works, perform a clean reinstall:

1. **Uninstall** DR Sim Manager from **Windows Settings → Apps → Installed apps**.
2. **Back up your profiles** — Copy the `Profiles` folder from `C:\Users\<UserName>\AppData\Local\DRSimManager\Profiles` to a safe location.
3. **Delete the data folder** — Delete the entire `C:\Users\<UserName>\AppData\Local\DRSimManager` folder.
4. **Download the latest installer** from [GitHub Releases](https://github.com/DepartedReality/dr-sim-manager-releases/releases/latest).
5. **Install** DR Sim Manager.
6. **Restore your profiles** — Copy your backed-up `Profiles` folder back to `C:\Users\<UserName>\AppData\Local\DRSimManager\Profiles`.
7. **Reactivate your license** — Enter your license key and email when prompted.
8. **Reconfigure** — Set up your sim config, outputs, and settings.

{% hint style="info" %}
A clean reinstall removes all settings and starts fresh. Your license key is stored on the server, so you can always reactivate on the same machine.
{% endhint %}

***

## Application Error Dialogs

If DR Sim Manager shows an error dialog on startup, the message provides clues about the issue:

* **"A critical system error occurred"** — This indicates a serious system-level error such as a hardware disconnection, memory access violation, or graphics driver issue. Try restarting, checking hardware connections, and updating drivers.
* **"An application error occurred"** — This is a non-critical error. Try restarting the application, checking configuration settings, and ensuring all required files are present.

In both cases, the log file will contain more detailed information. See [How to Check Logs](#how-to-check-logs) above.

***

## Still Not Working?

1. **Share your log file** — The log file is the most important piece of information for diagnosing startup issues.
2. **Contact support** — Email **<info@departedreality.com>** with your log file and a description of when the issue started.
3. **Join Discord** — The [Departed Reality Discord](https://discord.gg/skn2HzpbQy) community can help troubleshoot.


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