> For the complete documentation index, see [llms.txt](https://help.iodd.kr/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.iodd.kr/troubleshooting/faq.md).

# FAQ

### 🔐 Password & Security

<details>

<summary>I entered the correct password, but it says "Incorrect."</summary>

You must enter the user identification prefix before your password.

* **Admin**: Enter **0** + \[Your Password]. (e.g., if your password is '1234', enter '01234')
* **Users**: Enter **1\~4** + \[Your Password]. Refer to: [Encryption Guide](/aes256-encryption-mini-pro-st-lk/encryption-guide.md)

</details>

<details>

<summary>I forgot my password. Can I recover my data?</summary>

**No.** It is absolutely impossible for anyone, including the manufacturer, to recover or find a forgotten password. The data is hardware-encrypted.

</details>

<details>

<summary>I forgot my password. How can I reuse the IODD?</summary>

The only way to reuse the device is to **Reset Password**. All existing data will be permanently lost during this process.

* 2541 : [2541 Reset Password](/troubleshooting/iodd2541-reset-password.md)
* MINI : [MINI Reset Password](/troubleshooting/iodd-mini-reset-password.md)
* ST400, LK100 : [ST400 Reset Password](/troubleshooting/st400-lk100-password-reset-sa.md)

</details>

<details>

<summary>After entering my password, the screen shows "PLEASE WAIT" and then stops.</summary>

For **ST300, ST400, MINI PRO, and MINI** models, if the device stops responding on the **PLEASE WAIT** screen after password entry, use the following procedure to re-flash the firmware:

Hold **`9`** and **`Enter`** while connecting the USB cable. Continue holding both keys for **7 seconds** to force a re-flash.

Refer to the [Firmware Update Guide](/troubleshooting/firmware-update.md) for the updater download and full procedure.

</details>

***

### 💻 Booting & Virtual Drive

<details>

<summary>The IODD will not boot from the PC.</summary>

Please refer to the [Booting Error Guide](/troubleshooting/booting-error.md) for detailed troubleshooting steps.

</details>

<details>

<summary>When I mount a VHD, the mode changes to CD-MODE automatically.</summary>

This is often caused by the filename or default settings. Legacy models (2531/2541) use filename extensions like `.VHD` (Fixed) and `.RMD` (Removable) to control mode behavior. Refer to the [VHD Advanced Naming Guide](/appendix/appendix.md#vhd-advanced).

</details>

<details>

<summary>How can I unmount virtual drives?</summary>

* **ST/MINI PRO**: Navigate to the file and press the select key, or use the **\[7]** eject hotkey.
* **Legacy**: Press and hold **\[7]** for 3 seconds, or use the **Menu -> Advanced -> Umount VHDD** option.

</details>

***

### 🛠️ Hardware & Maintenance

<details>

<summary>My SSD write speed has become noticeably slow.</summary>

If your SSD's write speed has degraded, performing a **TRIM** operation will greatly improve performance.

* **Why TRIM?**: USB-connected external SSDs typically do not receive automatic TRIM commands from Windows. Running TRIM manually clears unused data blocks, preventing speed degradation and extending the SSD's lifespan.
* **How to fix**: Use the [**IODD TRIM Tool**](/various-functions/iodd-trim-tool.md) to perform a "Free Space TRIM" (safely optimizes without losing data) or a "Full TRIM".
* **SLC Cache Tip**: Most modern SSDs use an "SLC Cache" for fast initial writes. Once the cache is full, speeds drop significantly. After a large file transfer, **leave the IODD connected to USB power for about 10 minutes** before unplugging. This gives the SSD controller enough idle time to flush the cache and reorganize data, ensuring fast speeds for your next use.

</details>

<details>

<summary>The LCD only displays "IODD [Model Name]" and does not progress.</summary>

This indicates a system hang or corrupted firmware. Please perform a [Firmware Update](/troubleshooting/firmware-update.md) or use the **Emergency Recovery Procedure** (Section 15.2 in the [Appendix](/appendix/appendix.md#legacy-details)).

</details>

<details>

<summary>The touch sensitivity of the buttons is poor (2541).</summary>

For older units, placing a thin piece of paper or plastic film between the internal drive and the front body (not the cover) can improve responsiveness.

</details>

<details>

<summary>The firmware update fails repeatedly.</summary>

Ensure you are using a stable USB port (rear of the PC) and have only one IODD connected. Refer to the [Firmware Update Guide](/troubleshooting/firmware-update.md).

</details>