(Note: the following is a long version of the story. If you want the short version, just the solution, skip to the last paragraph below.)
As I wrote before, I use virtual machines extensively to do work on my computer. I used Windows XP Pro as the host OS for several years now, and it worked quite well. I skipped Vista and kept using XP, mainly because it did not seem like Vista would add any significant benefits to my host computer. However, a few months ago, Windows 7 became available, and while testing my products with it, I was so impressed with its speed, stability, the look and feel, that I decided it was time to upgrade my main host computer to Windows 7.
So, a week or so ago, after backing everything up, I took the plunge and installed a fresh copy of Windows 7 Ultimate. It went well, I was happy. Of course the first application I added to it was Virtual PC, because I needed it to run my virtual machines that do the real work for me. It went well, except for a few surprises, such as the new user interface of the Virtual PC console, that looked like a regular folder rather than a separate program. Also, it upgraded the integration components of my virtual machines and as a result it started using the Remote Desktop to display the virtual machine desktop. It added the ability for the virtual machines to recognize the USB drives attached to the host, but at the same time it downgraded the display capability of the virtual machine to display 16-bit colors only, that caused the fonts on the virtual displays not to be anti-aliased quite as nicely as before.
Those were minor things, though, and after trying my virtual machines for a couple of days, I decided I could live with the new version of Virtual PC. One thing did bother me, though: when I tried to browse the shared network folders from within the virtual machines, the browsing was quite slow. Literally, it took a few seconds just to navigate from a directory to a subdirectory. It was especially bad if the directories contained a lot of files. Copying files over the network was painfully slow, too. However, the network was slow only when using it from within the virtual machines. Outside, the network was as fast as it was before: I could browse the virtual machines from my host computer, and connect to other “real” computers from it, the speed was as usual.
I searched the web and found a few reports from people describing the same problem, but no real solution. The only suggestion was to replace the new version of Virtual PC software with the previous one, Virtual PC 2007. Although Microsoft does not officially support Virtual PC 2007 on Windows 7, a few posts I found suggested that it was quite possible to install and use VPC 2007 on Windows 7.
After contemplating it a bit, I decided that having fast network access from within the virtual machines was worth the trouble and did just that: uninstalled the new Virtual PC, and installed the previous VPC 2007 with SP1. The good news was that even though the virtual machines were previously updated with the new version of the integration components, they kept working well with VPC 2007, as before: the full 32-bit colors of the display were available, the old console window was back, and most importantly, the network access was as fast as before.
I was happy for a couple of days, until I noticed a strange problem happening: after using the virtual machines for some time, while switching back and forth between them and the host computer, at some point the virtual machines would stop accepting the TAB and ESC keys. That was a new problem that I did not experience before. Again, I started searching the web for a solution, and found a couple of suggestions, such as the one about creating a local security policy for the file VPCKeyboard.dll, but none of the suggestions worked: after several minutes, the TAB and ESC keys would stop working in the virtual machines (all of them at once), and the only way to restore them was to shut down all virtual machines, and restart the Virtual PC console application. Then work for a few minutes and do the restart again. Needless to say, that was extremely annoying.
Having spent two days trying every possible thing I could come up with, including searching for the updated drivers, reinstalling the virtual machine additions, trying alternative ALT+TAB managers, turning the Aero theme on and off, and so on, I decided that having the slow network was not as bad as it seemed after all. I removed VPC 2007, and reinstalled the new version of Virtual PC software. The TAB/ESC keys problem went away, the slow network access returned, and I started searching the web for a solution again. Accidentally, I came across of an old Microsoft support article that applied to Virtual PC 2004 and Virtual Server 2005, that mentioned a solution to a problem of a slow network access similar to what I’ve experienced. Out of desperation, I decide to give it a try, and … it worked! I guess, this problem was fixed in VPC 2007, but resurrected in the new version of Virtual PC (the old bugs are had to die, it seems). Anyway, here is what solved the slow network access in Virtual PC for me (from the Microsoft support article , Method 2):
- On the host computer, backup the Registry, just in case, and then:
- Run Registry Editor (regedit.exe) and select the following key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
- Create new DWORD value named DisableTaskOffload and set its value to 1.
- Restart the computer.
After I did the above, the network speed from within the virtual machines became as fast as it was before. Hope this helps someone!



February 17th, 2007 at 10:10 pm
I believe that this is because there is an NTFS fork on the directory that says that anything in that directory shouldn’t be trusted. This is similar to XP in how it knows that a file was downloaded recently by IE.
February 19th, 2007 at 6:06 pm
Hi Andrei,
Have a quick question about TweakUAC. Can I suppress UAC messages only for a single application using TWeak? Or does it suppress all UAC messages, system wide?
Thanks.
Regards,
Soumitra
Hi Soumitra,
> Can I suppress UAC messages only for a single application using TWeak?
No, it’s impossible.
> Or does it suppress all UAC messages, system wide?
Yes, that’s how it works.
Andrei.
February 20th, 2007 at 11:22 am
Hi Myria,
> I believe that this is because there is an NTFS fork on the directory that says that anything in that directory shouldn’t be trusted. This is similar to XP in how it knows that a file was downloaded recently by IE.
It may very well be so, but it does not make it any less of a bug. If a file contains a valid digital signature, Windows should not misrepresent it as coming from an unidentified publisher.
Andrei.
February 26th, 2007 at 1:09 pm
How did you take a screenshot of the UAC? I can’t get Print Screen to copy it to the clipboard, and the snipping tool isn’t working either.
February 26th, 2007 at 9:55 pm
Hi Chris,
> How did you take a screenshot of the UAC? I can’t get Print Screen to copy it to the clipboard, and the snipping tool isn’t working either.
Those tools don’t work because UAC displays its messages on the secure desktop, to which the “normal” user tools have no access. To solve this problem, I’ve changed the local security policy to make the UAC prompts to appear on the user’s desktop. After that, I used the regular Print Screen key to capture the screenshots.
Hope this helps,
Andrei.
March 4th, 2007 at 2:58 am
Hi Andrei,
I sell software to a *very* non-technical customer base. My setup procedure includes installation of an .ocx file into the \windows\system32 folder and registration of it using regsvr32. In order to copy anything into the \windows\system32 folder under Vista I have to turn off UAC. I would like to be able to do this automatically, programmatically, so I don’t have to make my users mess with UAC. I’d like to be able to turn off UAC for a second or two programmatically, then turn it back on. Will your software enable me to do that?
Thanks
March 4th, 2007 at 11:42 am
Hi Matthew,
> I’d like to be able to turn off UAC for a second or two programmatically, then turn it back on.
Unfortunately it’s impossible: if you enable or disable the UAC, Windows must be restarted before the change would have take effect.
To solve your problem:
> In order to copy anything into the \windows\system32 folder under Vista I have to turn off UAC.
It looks like your setup process is executing non-elevated, that’s why it cannot do that. You may want to try to start it elevated and see if it would have solved the problem without turning off the UAC.
HTH
Andrei.
March 25th, 2007 at 10:24 am
don’t use TweakUAC because this program makes your Vista unsafe!
March 29th, 2007 at 10:30 pm
> How are you supposed to make the decision whether to trust a certain program or not if UAC does not provide you with the correct information? (Nevermind, it’s a rhetorical question).
The answer is you are not. A guest should not be allowed to make any decision about installing software. If you log on as a valid user, the prompt works just fine. If you log on as a guest, you shouldn’t be installing software, so any dire warning is fine.
Yes, this might be unintended behavior (or perhaps it is not), but its impact is null.
March 31st, 2007 at 4:47 pm
Hi Herbys, you wrote:
> The answer is you are not. A guest should not be allowed to make any decision about installing software.
Sorry, but you are missing the point: the UAC displays this information for the _administrator_ to use and to make a decision, not for the guest user. The administrator is supposed to review the information and enter his or her password to approve the action. Take a look at the screenshot and see for yourself.
> If you log on as a guest, you shouldn’t be installing software
Why shouldn’t I? What if I want to install a program for use by the guests only? For example, I use only one web browser (IE), but I never know what browser a guest may want to use. So, being a good host
I want to install also Firefox and Opera, but I don’t want them to clutter my desktop, etc., I want them to be used by the guests only. To achieve that, I would log in to the guest account and install the additional browsers from there.
> so any dire warning is fine.
Wrong.
> Yes, this might be unintended behavior (or perhaps it is not), but its impact is null.
May be, may be not. In any case, it does not make it any less of a bug!
April 10th, 2007 at 9:28 pm
Is there any plan to adapt your program into a Control Panel Applet? I think that would be very clever.
April 11th, 2007 at 9:07 am
Hi Timothy, you wrote:
> Is there any plan to adapt your program into a Control Panel Applet?
No, we don’t have such plans at this time, sorry.
June 18th, 2007 at 9:19 pm
Anyone know why Vista won’t let me rename any new folder?
The permissions are all checked for me as administrator, still I get an error message, “folder does not exist”. I can put things in folder and move it, but can’t rename it?
January 29th, 2008 at 9:46 am
To be honest, I have always thought that digitally signing was merely a way of generating more revenue. It doesn’t offer you any more security and windows will always moan at you regardless of an application having a signature or not.
Even if your application has the “all powerful” and completely unnecessary Windows Logo certification, it still offers nothing to you as a user other than the reassurance that the person/s developing the software has allot of spare cash.
February 24th, 2008 at 10:34 am
Bob Said:
> To be honest, I have always thought that digitally signing was merely a way of generating more revenue.
I have to agree. I’ve heard the argument of how it’s all designed to protect users from malicious software, and that’s all well and good as far as that goes — but since Vista, and most mobile OSes, don’t offer a way for users to say “okay, I understand the risk, I accept full responsibility, please go ahead and run this unsigned application without restrictions, and never bother me again when I try to run this application”… That makes it pretty clear it’s just a racket initiated by VeriSign and the like, and happily endorsed by Microsoft.
May 17th, 2008 at 9:03 am
This is not a bug.
The first screen shot shows that Windows doesn’t trust the identity contained in the certificate. In other words, “I can read this, but I don’t know if I should trust the person who wrote it.”
The second screen shot just shows that the certificate is well-formed, that Windows can understand the information contained within it. It says nothing about what Windows will do with that information.
Who did you did you pay to sign the certificate for you? If they’re not someone with a well-established reputation, then I don’t WANT my computer to automatically trust them.
It’s just like how web browsers automatically trust SSL certificates signed by Thawte or Verisign, but will ask you before accepting a certificate from Andy’s Shady Overnight Certificate Company. As always, it’s a balancing act between usability and security.
May 17th, 2008 at 10:04 am
Andrew, you wrote:
> This is not a bug.
OK, there is a fine line between a bug and a feature, let’s assume for a moment that it’s a feature rather than a bug. If so, what benefit is this feature supposed to provide? As the second screen shows, the file is digitally signed, and Vista can detect that. Yet, it shows the publisher as “unidentified” on the first screen. Note also (as I mentioned in the post), that if you move the file to one a few specific folders (such as C:/Program files), Vista would magically begin to recognize the publisher. Move the file to some other folder, and it’s unidentified again.
If you can explain why they designed it that way, I would agree with you. Until then, it’s a bug. Guilty until proven innocent!
> Who did you pay to sign the certificate for you?
That particular file was signed with a Verisign certificate, but the same problem occurs with _any_ file, signed with _any_ certificate. Try it yourself and you will see.
June 1st, 2008 at 12:53 pm
I think that it occurs because of IE7 protected mode – see http://victor-youngun.blogspot.com/2008/03/internet-explorer-7-protected-mode-vs.html, it’s a guide to run firefox in protected mode, and this explains very good how the protected mode works… the prompt is because the “Download” Folder is a protected folder (level “low”) and I think it only displays at the guest, because Windows forces UAC to display certificate in normal user mode in “low” level folders, but NOT for the MUCH MORE RESTRICTED “guest” account. This would be my explanaition.
It doesn’t mean that I like it how Microsoft handels this but this would eventually explain WHY the warning appears sometimes and sometimes not.
June 1st, 2008 at 12:55 pm
sorry, in my last post there is a comma in the link, the correct link is:
http://victor-youngun.blogspot.com/2008/03/internet-explorer-7-protected-mode-vs.html
June 3rd, 2008 at 7:16 pm
Farthen: thank you for the information and explanation!