Windows 7 Windows 7 (64) - Missing sound Card on UEFI setup

It seems like you are experiencing an issue with the sound card not being recognized when using UEFI mode on your Dell Latitude E6520, whereas it functions properly in Legacy BIOS mode. Here are a few considerations and troubleshooting steps you can take to address this problem: 1. Secure Boot Compatibility: - UEFI mode often incorporates Secure Boot functionality, which is designed to protect the system from malicious software. It's possible that Secure Boot might be causing compatibility issues with the sound card. - Check if there are any Secure Boot settings in the UEFI BIOS and try disabling Secure Boot to see if it resolves the sound card detection issue. 2. UEFI BIOS and Drivers: - Ensure that your UEFI BIOS is up to date. Check Dell's support website for any BIOS updates specific to your Dell Latitude E6520 model. - Update the drivers for the sound card. Sometimes, certain drivers are required for proper functionality in UEFI mode. 3. UEFI Configuration: - Review the UEFI settings related to system configurations. Look for any settings that might affect the compatibility or detection of hardware devices. 4. Hardware Compatibility: - Verify that the sound card is fully compatible with UEFI systems. Some older components or drivers may have limitations or issues with newer UEFI interfaces. 5. BIOS/Firmware Bug: - It's also possible that there may be a bug in the BIOS or firmware that affects the detection of the sound card in UEFI mode. Checking for any known issues or updates from Dell could be beneficial. 6. Windows Compatibility: - Ensure that your Windows 7 (64-bit) installation is fully updated with the latest Windows Updates. Sometimes, updates from Microsoft can resolve hardware compatibility issues. 7. Testing: - If possible, try booting from a different operating system (such as a live Linux distribution) in UEFI mode to see if the sound card gets recognized. This can help determine if the issue is specific to Windows 7 or a broader compatibility issue. By investigating these factors and following the troubleshooting steps, you may be able to pinpoint the cause of the sound card detection issue in UEFI mode on your Dell Latitude E6520 and potentially resolve it.