Vista’s UAC Failing Once Again

Ok, so before I delve into detail, I should give a background on what exactly I’m talking about first.  Saturday night I was talking to Ryan Price about some issues that he was seeing with Windows Vista.  The main issue that he was concerned with was a rather odd boot delay when Vista was starting up.  It seemed that it would just hang between the logon screen and getting to a usable desktop.  So I kept this in the back of my head, and today while I was looking for something completely unrelated, I came across what seems to be the culprit responsible for this issue.

I came across an entry in my event log that reported "luafv" successfully starting.  It perked my curiosity and upon looking into it further I discovered that this was the LUA File Virtualization Driver which is responsible for virtualizing file and registry writes in Vista providing UAC is ENABLED.  So of course I immediately wondered why this driver would be attempting to load when UAC was disabled on my system.  Could this be what is causing the hang?  Well there was only one way to test it.  Re-enabling UAC seemed to yield a slightly faster bootup time which was good and so far supported my theory.  But here is where things really got interesting.  Disabling UAC and then subsequently disabling the luafv driver yielded and even quicker boot time than having UAC enabled.  So the driver was hanging, hence causing the issue, but it is rather weird that the driver takes what seems to be so long to load even on a UAC enabled system.  Below are some tests that Ryan ran as well as a test of my own to support these findings.  Note that the best boot times were achieved with UAC AND the LUAFV driver DISABLED.

 

Ryan’s Desktop – Vista SP1 17042

UAC Disabled w/o Tweak – 1 min 50 sec.
UAC Enabled – 1 min 30 sec.
UAC Disabled w/ tweak – 1 min 12 sec.

System configuration: 2.4 Ghz Dual Core AMD Opteron 165 , 4 GB DDR500 , Geforce 8500GT, Windows Vista Ultimate x64 SP1 RC1

Laptop – Vista RTM

UAC Enabled: 2 minutes 25 sec.
UAC Disabled w/ tweak: 1 minute 45 sec.

System Configuration: 1.6 Ghz Pentium Dual Core, 1 GB DDR2 533 , Intel Mobile Graphics 950. Windows Vista Home Premium RTM

My Test – Vista SP1 17042

UAC Enabled: 1 minute 38 sec.
UAC Disabled w/ Tweak: 1 min 04 sec.

System Configuration: XPS M1710, 2 GHZ Core2 T7200, 2 GB DDR2, 7950GTX

So, as you can see this seems to be a real problem that has been stumbled upon, and is one of the largest complaints about Vista these days (slow bootup and unexplained delays).  One other thing to note, this issue is persistent across Vista RTM and the current beta build of Vista SP1 (6001.17042).

How should Microsoft go about fixing it?  Well my solution is easy, make it so that when UAC is disabled, so is the LUAFV driver since it is obviously not needed on a UAC enabled system, this will allow people to disable UAC and not see a bootup performance hit, when the reality is that it should be the other way around, as proven by our testing.

Last but certainly not least, I want to thank Ryan for his time in testing this.  I wanted to be sure I had some concrete and verifiable results before I posted something about this.  This combined with a few other tweaks should largely solve many of the user complaints about Vista.  I will post these tweaks in detail once they have been fully tested and confirmed to not cause any adverse side affects to the system.

Posted by: Chris123NT

Published on: November 27th, 2007 at 12:19 AM

Posted in Tips and Tricks, Windows Vista

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14 Responses to 'Vista’s UAC Failing Once Again'

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  1. December 15, 2007 at 2:46 am

    dav:

    this news is pure FUD.

  2. December 15, 2007 at 4:38 am

    Ace DDL » Disabling UAC Slows Vista’s Bootup Time?:

    [...] source: Chris123NT's Blog (Thanks hypatech & [...]

  3. December 15, 2007 at 5:21 am

    Steve:

    I cannot confirm that this works – did the same tests on a

    Vista Ultimate machine 32 bit, Intel Core 2 Duo E6850 3Ghz with 4GB of RAM

    and the start up time is almost exactly the same no matter whether I have enabled that ‘tweak’ or not …

    Must be configuration specific if you see such differences …

    Steve

  4. December 15, 2007 at 6:32 am

    doktor:

    I agree with Steve. Just a minute ago I performed the test with Windows Vista Ultimate 32bit almost exactly same times. Maybe this “tweak” works in 64bit versions only?

  5. December 15, 2007 at 11:45 am

    Alex:

    This is interesting. I wonder how this relates to a similar delay I have experienced: Windows loads to the desktop, then pauses with only part of my startup programs loaded, no HDD activity, nothing for about 15 seconds. I’ve seen this on other laptops besides mine. I looked it up and found a solution which has fixed the problem for me: disabling the ‘Workstation’ service. This completely gets rid of that delay for me. Is this blog talking about the same delay? Are these issues related?

    I want to try this tweak described in this blog entry, but I dont see any descriptions anywhere of what to do exactly… where can i find that information?

  6. December 15, 2007 at 12:09 pm

    Brandon:

    UAC is there for a reason, I don’t disable it, I hardly see it, only when installing a game, or chaning my network location, no biggie.

  7. December 15, 2007 at 3:14 pm

    [Chris123NT blog] Vista’s UAC Failing Once Again - Overclock.net - Overclocking.net:

    [...] that the best boot times were achieved with UAC AND the LUAFV driver DISABLED. Read more @ Source: Chris123NT blog __________________ [...]

  8. December 17, 2007 at 11:56 am

    fu:

    Flame bait article aka dumbass.

  9. December 31, 2007 at 8:07 am

    Tony:

    I had disabled UAC and noticed that after a while my compuer was hanging for about 2-3 mins during boot up. After reading your article, I re-enabled UAC. For about 1 to 2 weeks, I continued to experience the hang during reboot. Then I suddenly noticed that the computer is no longer hanging. It’s back to rebooting normally – about as quick as when I first installed Vista.

    I am runnning Vista Home Premium on a Quad core Q6600 with 4 GB of memory and NVidia 8500 with 256 MB. This system rocks with Vista. Overall, I am quite happy with Vista (as long as the hardware can handle it).

  10. January 23, 2008 at 1:13 pm

    MagnumMan:

    I’ve found on Vista Enterprise x64 SP1 RC with a Phenom 9600 and MSI K9A2 Platinum that if I use 4 memory modules, and try to boot with UAC enabled, Vista hangs on startup and the system restarts itself. It doesn’t even get to the login page, and is reproducible with safe mode. Then using System Restore in recovery mode I go back to a previous state where UAC is off, and the system boots. I guess UAC is just pure evil. :>

  11. May 20, 2008 at 6:31 am

    cause of latency:

    [...] which controls UAC in Vista, can cause latency issues if the controversial feature is disabled.http://chris123nt.com/2007/11/27/vistas-uac-failing-once-again/File Creation Latency Test in the Solaris 10 Operating SystemFile Format: PDF/Adobe Acrobatsame [...]

  12. July 30, 2008 at 8:23 am

    A Little Lie and You'll Like Vista - Page 3 - Xtreme CPU:

    [...] “Start”=dword:00000004 For more info please visit Chris123NT’s Page. ————————————————– __________________ The Phantom Of The [...]

  13. August 19, 2008 at 2:30 pm

    Joomla & Vista - Vista Forums:

    [...] Its not a issue for everyone with superfast computers, some do have this problem while others dont…Its also just something most people dont care about since they never check there Performance logs (Event_ViewerApplications & Services LogsMicrosoftWindowsDiagnostics-PerformanceOperational) You can see the time takes to boot drivers and services from there, I dont disable UAC so I dont know if this problem still exists, I think it was partially fixed for 85% of users not using UAC when ServicePack1 was released this year… Find out for yourself, just look at the Performance Log boot times with UAC enabled over a few days then do the same with it turned off and compare the average boot time…You will find it boots faster with UAC enabled. This is the original article I read a few months ago just before SP1 was released…Chris123NT is a highly respected Microsoft MVP Chris123NT’s Blog » Publications » Vista’s UAC Failing Once Again [...]

  14. August 25, 2008 at 4:50 am

    Vista: Simpler is NOT Always Better - Page 2 - Xtreme CPU:

    [...] "Start"=dword:00000004 For more info please visit Chris123NT’s Page. ————————————————– [...]

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