Office 2010 Beta adds Local Disk (Q:) to the system

Posted: December 18, 2009 in Office 2010, Windows 7, Windows Vista, Windows XP
Tags: , , ,

I’ve recently noticed that my system has a new local disk, named Q:

Local Disk (Q:) - Where did it come from?

While I was curious as to how this disk came about, given that no one else uses my computer, I wasn’t too bothered about it. Last night, while working with a friend, I was asked a question - “What’s that Local Disk (Q:)? I’ve got one on my system too and it popped out of nowhere.”

Naturally, I started digging.

The first place I checked was the Disk Management Utility and what I found there was weird.

The disk isn’t there, but then it is.

Disk Management Utility - Q: is not there

I tried to open the disk via Windows Explorer and got an “Access is Denied” error.

Access is Denied

I then took a look in the registry, checking HKLM\SYSTEM\MountedDevices and as expected, Q: was there.

HKLM\SYSTEM\MountedDevices - Q: is there

So what is this mysterious Q: that’s there, inaccessible and not a partition of any existing physical drives?

At this point, I was totally lost. It still hasn’t hit me that this drive appeared right after installing Office 2010 Beta.

I continued digging and the answer was found on the Microsoft Office 2010 Engineering Blog’s post on a new feature in Office 2010 – Click-to-Run . This new drive that has appeared in the system, is part of the all new “Click-to-Run” feature in Office 2010.

Office 2010 Click-to-Run is a virtualized application that is stored on Microsoft’s servers. Whenever one launches any of the Office applications as “Click-to-Run”, the system will download the necessary components to the virtual disk (Q:).

Office 2010 Click-to-Run - Downloading files

How does this benefit us?

Easy. Firstly, no updates to install. All updates will be installed on Microsoft’s servers and we’ll always have the most up to date version of Office 2010. In addition to this, since Office 2010 is installed on a server, we’ll be able to take Office 2010 with us anywhere we go. As long as there’s an internet connection, we will be able to use all Office applications that we are licensed to use. This is made possible by both “Click-to-Run” and  the Microsoft Office To-Go Device Manager.

Microsoft Office to go Device Manager

So that’s it. More detailed information on “Click-to-Run” and the “Microsoft Office To-Go Device Manager” is available on the Microsoft Office 2010 Engineering Blog.

Now you can rest easy knowing that the drive is there for a reason.

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  1. [...] December 26, 2009 proteus555 Leave a comment Go to comments Those who have read my previous post on Office 2010’s “Click-To-Run” feature would understand why Local Disk (Q:) was [...]

  2. Gianluca says:

    yeh ok so we know now, but after uninstalling it via an uninstall manager that deletes all reg files belonging to office 2010 i still get that error….how do i remove it

  3. [...] release? Would a person actually need to access Disk Q for any reason? Oh well, we'll see. Office 2010 Beta adds Local Disk (Q to the system BTW: MS Office 2010 beta is a free download to use until Oct 2010 It is a big hog…JMHO [...]

  4. Aarowaim says:

    So, I can’t use MS 2010 Beta without internet connection?

  5. [...] it without removing Office 2010 Beta see these threads.. Office 2010 Beta – Phantom Q drive Office 2010 Beta adds Local Disk (Q to the system Hide Local Disk (Q added by Office 2010 Beta Reply With Quote + Reply to [...]

  6. [...] drive Here's a bit more on the phantom Q drive here… Office 2010 Beta – Phantom Q drive Office 2010 Beta adds Local Disk (Q to the system Hide Local Disk (Q added by Office 2010 Beta Reply With Quote + Reply to [...]

  7. Bob says:

    Thanks for the info. After uninstalling Office 2010 beta and click to run, I still have a Q drive which is still inaccessible. I cannot download a new Office 2010 because the drive is inaccessible. Can’t take it off, can’t use it. I am really starting to hate this new software. I cna’t even get rid of Q through disk management (no ability to “remove” or do anything else to Q for that matter). Maybe I need a superadministrator privilege???

  8. [...] online, I discovered that Disk Q is created by Microsoft Office Starter 2010, the OEM-packaged version of Microsoft’s office suite. The phantom drive is created when you [...]

  9. TERRI says:


  10. wtf says:

    Can’t believe there is still someone in 2011 that doesn’t know a xxxxxxx thing about computers lol.

  11. FishBizkit says:

    Here’s the way to remove the Q. Go to your Ctrl Panel & remove “Microsoft Office Click-to-Run 2010″ from Add/Remove Programs. TADA! No more Q.

  12. asterismW says:

    THANK YOU! I had a similar problem on our work computers. We didn’t have Office 2010 beta installed (it was the full version), but there was still a “ghost” drive, though for us it was a V: drive (perhaps because our Q: drive was already mapped to a network drive?). I could not for the life of me figure out where that drive came from or how to remove it. Then I stumbled upon your post, which explained what it was. The helpful comments led me to removing it. Uninstalling Office 2010 didn’t work, but there was another application listed in Programs and Features: Microsoft Application Virtualization Desktop Client. I uninstalled that, and the drive went away. Hooray!

  13. [...] It turns out that some installation of Microsoft Office install a “Phantom Drive” that seems to appear as “Q:” on users machines.  This is related to a tool called “Microsoft Office Click-to-Run 2010″.  You can read more about this particular issue here. [...]

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  15. Tag says:

    Just so I understand this. Deleting the Q drive will make the access to Office from remote computers unavailable but Office will work well on my computer?

    Thank you.

    • proteus555 says:

      Well, if you delete it, then the portability of office applications may be impacted. The steps I provided is to simply hide it from sight.

      • Tag says:

        Thank you for response. I discovered, after I left my message, that the ‘Q:” drive has the Lenovo quick start system in case of a crash. Sorry for the error and I appreciate your responsiveness.

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