Internal SATA drives are treated as removable drives - Solution

This is happening because Windows 7 added support for eSATA functionality. Some hardware vendors have incorrectly configured all SATA ports as eSATA ports. This causes all internal and external SATA devices to be treated as removable. This issue can affect hard disks, DVD drives, and other hardware attached to the internal SATA ports of the system.

This issue can be ignored because it does not have an effect on your computer. To resolve this issue you should contact the computer manufacturer for a BIOS update or other type of resolution to correct the misconfiguration of the internal SATA ports.

To work around the issue, a registry key can be set to change the behavior of the SATA ports.
Adding the TreatAsInternalPort value and setting it to 1 will cause a SATA port to be treated as an internal port and attached devices will no longer be considered removable. This value can be applied to specific ports as needed. To do this, follow these steps:

1.       Click Start
2.       In the Search programs and files box, type command
3.       In the Programs list, click Command Prompt and click Run as administrator
 If you are prompted for an administrator password or confirmation, type the password or click Continue.
4.       Copy and paste or type each of the commands into the command prompt and press Enter after each command
reg.exe add "HKLM\SYSTEM\CurrentControlSet\Services\msahci\Controller0\Channel0" /f /v TreatAsInternalPort /t REG_DWORD /d 0x00000001
reg.exe add "HKLM\SYSTEM\CurrentControlSet\Services\msahci\Controller0\Channel1" /f /v TreatAsInternalPort /t REG_DWORD /d 0x00000001

5.       Restart your computer to enable the registry changes
Note: There may be some trial and error to determine the correct ports (also referred to as "channels").
The channel numbers shown in Device Manager may not match the channel number in the registry, so you may need to set the value and verify the desired effect.