App-V: Hiding the Q: Drive

In some business environments the end users are particularly touchy about anything on the desktop changing, and when something does it results in helpdesk calls.  One of the changes that users often notice when you install the App-V client is the appearance of the Q: drive.  This is a virtual drive that is used to mount application packages.  They can see the drive but get an access denied when they try to browse to it.  So I sometimes get the question – can we hide it?

The answer is – yes!  And it’s easy, it just takes a quick registry change. By implementing KB article 555438 you’ll tell Windows Explorer to simply not display certain drives.  Note that the registry key is under HKEY_CURRENT_USER, so it only affects the current user.  If you add the value to the same path under the HKEY_LOCAL_MACHINE hive you’ll affect all users.

KB 555438: Hide physical drives in Windows Explorer

You’ll need to reverse the byte order listed in the article. The article describes how to create the NoDrives entry as a Binary value, but I prefer to use a 32-bit REG_DWORD.

For example, let’s say you want to hide Q and A, which are listed as 00 00 01 00 and 01 00 00 00 respectively, or 01 00 01 00 when combined. Let’s call these groupings A-B-C-D. When you enter the value in Regedit you’ll need to enter it as D-C-B-A, or 1 00 01 (leaving out the leading zeros). If you convert this to decimal you get 65537. If you only want to hide the Q drive you’ll get 10000 or 65536. You can enter the values in regedit in either hex or decimal formats.

On platforms newer than XP the Explorer key under Policies doesn’t appear to be created by default, so you’ll need to create it yourself. The registry changes should be picked up on the next logon.

Alternatively, you can follow KB 231289 to edit the System.adm file to modify it via a GUI:

KB 231289: Using Group Policy Objects to hide specified drives

The net effect of this is that users will not see the Q: drive and won’t click on it or browse to it through the normal file pickers.  You can still manually enter “Q:\” as your path if needed, and this doesn’t affect the command line.

Obviously if you’re not using Q you’ll want to change it to whatever letter you’re using for your environment.