Following the installation of Windows 7 RTM some users may find that their DVD drives will be rendered inaccessible, even though the devices functioned under normal parameters before the deployment of the latest Windows client. Microsoft noted that it was aware of the issue, and provided a few workarounds for the affected customers to regain DVD drive functionality. According to the Redmond company symptoms involve completely or only intermittently inaccessible DVD drives post-Windows 7 installations. According to Microsoft, there is an issue with the firmware for some DVD drive products and the Adaptive Link Power Management (ALPM) in Windows 7.

The software giant even revealed the specific devices that are affected by problems: “This problem may occur if you use one of the following DVD drives on the computer: Sony BC-5100S DVD, Sony BC-5600S DVD and TSST TS-L633B DVD+/-RW.”

According to Microsoft there are two workarounds that end users can turn to. The first is the simplest, and it involves updating the firmware for Sony BC-5100S DVD, Sony BC-5600S DVD and TSST TS-L633B DVD+/-RW. “To check for an applicable firmware update, contact the manufacturor of the DVD drive,” Microsoft noted.

At the same time, the Redmond company presents an alternative designed to let Windows 7 users regain DVD drive functionality in the eventuality that a firmware update is not available. The second mitigation involves disabling the Adaptive Link Power Management (ALPM) feature.

“ALPM is a feature that puts a hardware device into sleep state after 100 ms of idle time. This is a power-saving feature. After you disable ALPM, you can still configure the drive to run in any one of three power plans: Performance, Balanced, and Power Saver. However, you cannot still benefit from the additional power saving that is provided by ALPM,” Microsoft explained.

In order to disable ALPM users will need to first open a command prompt. Just enter cmd in the search box under the start menu and right click the selected result choosing Run as Administrator. There are a total of six commands that users must run, Microsoft revealed, all of them included below. Commands must be executed in this order:

powercfg.exe -setacvalueindex 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c 0012ee47-9041-4b5d-9b77-535fba8b1442 DAB60367-53FE-4fbc-825E-521D069D2456 0

powercfg.exe -setdcvalueindex 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c 0012ee47-9041-4b5d-9b77-535fba8b1442 DAB60367-53FE-4fbc-825E-521D069D2456 0

powercfg.exe -setacvalueindex 381b4222-f694-41f0-9685-ff5bb260df2e 0012ee47-9041-4b5d-9b77-535fba8b1442 DAB60367-53FE-4fbc-825E-521D069D2456 0

powercfg.exe -setdcvalueindex 381b4222-f694-41f0-9685-ff5bb260df2e 0012ee47-9041-4b5d-9b77-535fba8b1442 DAB60367-53FE-4fbc-825E-521D069D2456 0

powercfg.exe -setacvalueindex a1841308-3541-4fab-bc81-f71556f20b4a 0012ee47-9041-4b5d-9b77-535fba8b1442 DAB60367-53FE-4fbc-825E-521D069D2456 0

powercfg.exe -setdcvalueindex a1841308-3541-4fab-bc81-f71556f20b4a 0012ee47-9041-4b5d-9b77-535fba8b1442 DAB60367-53FE-4fbc-825E-521D069D2456 0