In Windows Explorer there is a drive letter which is not linked to any physical drive (at least I think it is not…). When I double-click on the drive a message appears saying ‘M: is not accessible. The parameter is incorrect’. Also, the M: drive does not appear in the Disk Manager console. The properties of the drive are ‘File system unknown, Capacity 0, Used 0, Free 0′. How can I get rid of this non-existent drive?

Before removing the drive from Windows Explorer we need to make sure the M: drive is not pointing to a real physical drive. Since the M: drive does not appear in the Disk Manager console we can be fairly certain that this is not a real drive, but it is worthwhile double-checking. First, check whether you have any external drives connected to the computer (e.g. external hard drive, or thumb drive) which could be linked to the M: drive. This is probably not likely, since the properties for the drive indicate there is no data on the phantom drive. The next most likely scenario is a memory card reader being connected to the computer. Windows will recognise memory card readers as external drives, but will not be able to access the drive until a memory card has been inserted into the reader. If you don’t have an external memory card reader, check the front of the computer (as some newer computers come with memory card readers installed in one of the front-bays in the computer), and you should also check the monitor (as some flat panel monitors come with card readers in the side of the monitor).

Assuming you have exhausted the search and there is definitely no physical drive connected to the M: drive, we should be able to remove this drive from Windows Explorer. Windows allows for certain drive letters to be hidden. This means that while the drive is still technically present, it will be hidden and not visible (so it no longer clutters the Windows Explorer interface). To hide the drive we will need to edit the Windows registry, and this procedure has some tricky aspects to boot. So, only proceed if you are confident with editing the registry.

In order to hide a drive, you need to specify the ‘mask’ for the drive letter in the registry. The masks are assigned based upon the following pattern: A=1, B=2, C=4, D=8, E=16,…,Z=33554432. To hide multiple drives, add the masks for the drives you wish to hide together, and add that value to the registry. This may seem a bit complicated (and you would be correct with that comment…) but it works. Even making it easier, there is a handy website (www.wisdombay.com/hidedrive) which allows you to just tick the drives you wish to hide and it will calculate the mask/value. In the case of the M drive, the relevant mask is 4096. Once you have the mask, go to the ‘Start’ menu > ‘Run’ and type ‘regedit’ (without the quotes) and click OK. In the Registry Editor window, navigate to the following registry key:
HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionPoliciesExplorer
Once you have arrived at this registry key, in the right-hand pane right-click in an empty space and select ‘New’ > ‘DWORD Value’. Name the value ‘NoDrives’. Right-click on the newly created ‘NoDrives’ value and select ‘Modify’. For the value data input the calculated drive mask, in the case of the M drive this will be 4096. Click OK. Close the Registry Editor and restart Windows. Upon rebooting the M: drive should be gone. Be aware, not all programs may honour the hiding of the drive. However, now that the drive has been removed from Windows Explorer this should at least make the setup a bit tidier.