However, one of my favourite features is the ‘Undo Disk’ functionality. I can boot the virtual machine up, and any changes I make are only temporary. When I shut the virtual machine down, I can either choose to keep those changes, or wipe the slate clean as if the virtual PC had never been booted up.

This evening, I found this most useful in installing a neighbour’s broadband connection. A lot of ISPs (especially in the UK) are adamant that you must install the software from their CD in order to setup your ADSL. Normally this is utter rubbish, and you can simply log on to the modem directly and fill everything in.

Not so with the BT Home Hub.

I’ve talked about these irritating pieces of kit before, but sadly our new neighbour ordered it before I knew she was getting ADSL so I didn’t have time to intercept with a better recommendation. I spotted the courier delivering the wretched thing this morning as I was sitting on the pavement trying not to die doing a manly warm-down after my morning run, and volunteered to set it up for her as I knew there was no way in hell she’d manage it on her own.

In fairness, this is a new breed of Home Hub, and it’s actually not as bad as the first. It did at least work properly, a significant improvement on the last one I dealt with. However, I couldn’t find a way to activate the BT Total Broadband connection without the BT CD, because instead of the username and password being entered on the router itself, it seems you have to activate the line by authenticating against a proprietary system that can’t be got to directly, only via the BT software. Thus, I had to install the CD. Naturally I knew that it wouldn’t stop at activating the line and would install a plethora of pointless BT-branded crapware, so instead of subjecting either my own or my neighbours computer to this onslaught, I ran it on a virtual machine I have set up for testing new software at work.

As predicted, it installed some needless diagnostic suite, a bunch of ad-sponsored software, and the Yahoo Toolbar, all without asking. Once it had finished, I checked that the internet connection was active on another computer, then closed the virtual PC, hitting the ‘Delete Changes’ button. If only removing all that junk was as easy on a real machine…

So, in summary, Virtual PC is useful for activating home ADSL connections without having to then spend the next 20 minutes cleaning your machine of all the unnecessary junk your ISP wants to force on you.

The issue has been reported by a handful of users on the Adobe Forums and some of my users ran into it after I began a test roll-out of Acrobat on our site yesterday.

These are the exact error messages we’re seeing:

Microsoft Visual C++ Debug Library 

Runtime Error! 

Program: C:\Program Files\Adobe\Acrobat 9.0\Acrobat\Acrobat.exe 

The application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.

and when attempting to view PDF files in Internet Explorer:

Microsoft Visual C++ Debug Library 

Debug Error! 

Program: C:\Program Files\Internet Explorer\iexplore.exe 

abnormal program termination 

(Press Retry to debug the application)

We often see odd problems with software running on our network due to the various configuration options we use that set our workstations apart from the average home computer (and a lot of computers in other schools, for that matter), and often trip up programs that haven’t been tested on domain workstations. I ran a trace using ProcMon to see if I could work out what was going on:

98959 11:29:15.6155113 Acrobat.exe 972 CreateFile \Device\Mup\ NAME INVALID Desired Access: Read Data/List Directory, Synchronize, Disposition: Open, Options: Directory, Synchronous IO Non-Alert, Attributes: n/a, ShareMode: Read, Write, Delete, AllocationSize: n/a
99021 11:29:15.6181294 Acrobat.exe 972 CreateFile \\mydomain\users\ SUCCESS Desired Access: Read Data/List Directory, Synchronize, Disposition: Open, Options: Directory, Synchronous IO Non-Alert, Attributes: n/a, ShareMode: Read, Write, Delete, AllocationSize: n/a, OpenResult: Opened
99100 11:29:15.6219431 Acrobat.exe 972 QueryStandardInformationFile \\mydomain\users\ SUCCESS AllocationSize: 0, EndOfFile: 0, NumberOfLinks: 1, DeletePending: False, Directory: True
99111 11:29:15.6222464 Acrobat.exe 972 CloseFile \\mydomain\users\ SUCCESS
99182 11:29:15.6254897 Acrobat.exe 972 CreateFile \\mydomain\users\ NAME COLLISION Desired Access: Read Data/List Directory, Synchronize, Disposition: Create, Options: Directory, Synchronous IO Non-Alert, Open Reparse Point, Attributes: N, ShareMode: Read, Write, AllocationSize: 0
99187 11:29:15.6257927 Acrobat.exe 972 RegOpenKey HKU\S-1-5-21-1708537768-2052111302-682003330-4640\Software\Adobe\Adobe Acrobat\9.0 SUCCESS Desired Access: Read
99189 11:29:15.6258324 Acrobat.exe 972 RegQueryValue HKU\S-1-5-21-1708537768-2052111302-682003330-4640\Software\Adobe\Adobe Acrobat\9.0\Crashlog NAME NOT FOUND Length: 144
99191 11:29:15.6258536 Acrobat.exe 972 RegCloseKey HKU\S-1-5-21-1708537768-2052111302-682003330-4640\Software\Adobe\Adobe Acrobat\9.0 SUCCESS
99192 11:29:15.6259012 Acrobat.exe 972 QueryNameInformationFile C:\Program Files (x86)\Adobe\Acrobat 9.0\Acrobat\Acrobat.exe SUCCESS Name: \Program Files (x86)\Adobe\Acrobat 9.0\Acrobat\Acrobat.exe
99193 11:29:15.6260191 Acrobat.exe 972 RegOpenKey HKLM\Software\Wow6432Node\Microsoft\Windows\Windows Error Reporting\Escalation NAME NOT FOUND Desired Access: Read

The suspicious line here is in red: Acrobat issued a CreateFile on the root of the DFS share hosting the redirected AppData, with CreationDisposition set to CREATE_ALWAYS; in other words, trying to overwrite the share… unsurprisingly this resulted in a NAME COLLISION since it already exists, and a call to Windows Error Reporting immediately followed.

As I had tested the software on my own laptop I first assumed that perhaps only non-Administrators were affected, but quickly put paid to that theory after checking in with a non-admin who was also testing the software who only had the problem on certain machines. After checking in with further users, I found that only our desktop workstations were affected, not laptops, regardless of which user logged in. Since the same user was affected on a desktop but not a laptop, I surmised the difference was likely to do with something specific the fact that our desktop computers are configured to redirect most users’ Application Data directory to a network share, in order to keep consistent program settings regardless of where they log on. The laptops are not configured in this way, so that users can more easily access their accounts while off-site and not connected to the network.

Taking a page from Mark Russinovich’s book (or blog, to be more precise), I setup one of my Windows Vista testbench workstations to generate a crash dump for Acrobat in order to analyse, and from reading through the stack trace it appeared the problem stems from the PDFLTerm() function in AdobePDFL.dll (remember this is a stack, so the cause of the issue is usually below all the exceptions):

ntdll!KiFastSystemCallRet
ntdll!ZwWaitForMultipleObjects+0xc
kernel32!WaitForMultipleObjectsEx+0x11d
kernel32!WaitForMultipleObjects+0x18
kernel32!WerpReportFaultInternal+0x16d
kernel32!WerpReportFault+0x70
kernel32!UnhandledExceptionFilter+0x1b5
msvcr80!abort+0xeb msvcr80!terminate+0x4d
Acrobat+0x422e
ntdll!__RtlUserThreadStart+0x6f
ntdll!_EH4_CallFilterFunc+0x12
ntdll!_except_handler4+0x8e
ntdll!ExecuteHandler2+0x26
ntdll!ExecuteHandler+0x24
ntdll!KiUserExceptionDispatcher+0xf
kernel32!RaiseException+0x58
msvcr80!_CxxThrowException+0x46
Acrobat_69630000!DllCanUnloadNow+0x68e27
Acrobat_69630000!PDFLTerm+0x645ce
Acrobat_69630000!DllCanUnloadNow+0x663df msvcr80!_NLG_Return

Armed with all of this, I quickly located the forum post I mentioned earlier where other users had found the same issue with Adobe Reader 9.0 under the same circumstances. As users of the free download of Reader, they were out on their own as Adobe have no obligation to give them one-to-one support. However, as someone who had just spent several thousand pounds buying Adobe software, including Acrobat, they would have to talk to me, so I called their UK support line.

As soon as I read out the error message to the agent I talked to (the very helpful Andrew Mitchell, for reference), he told me that he’d heard the exact same problem yesterday and that Adobe were aware of a problem producing this error. I mentioned my diagnostics and told him I suspected the AdobePDFL.dll, which he confirmed was the case. He put me on hold for a couple of minutes to talk to a senior technician, and when he returned, confirmed more of what I’d already found out.

Unfortunately, Adobe were only made aware of the issue very recently, and there is currently no ETA for a fix. I later got a follow-up email from Andrew which stated the following:

“Unfortunately because of the new-ness of the software we are unable to provide you with a direct solution to this issue as all solutions are experimental at this time.”

Translation: we’re still testing the patch for this. I was told I will be contacted again when a fix is available, but for the meantime, I would strongly advise you do not deploy Adobe Reader 9.0 or Adobe Acrobat 9.0 if your users’ have their Application Data directory stored on a network share.

My cousin and her husband were unfortunate enough to have one foisted upon them by BT, and had not been able to get the wireless working since it arrived – which was hardly surprising since the integrated wireless was not only not broadcasting its SSID, but appeared to be disabled entirely, despite several admin pages on the box claiming the contrary. After a few cursory searches of various forums, I quickly learned that this is not an entirely unusual problem.

If you are unfortunate enough to have to deal with this retrograde piece of rubbish, may I recommend the following resources:

• Lock your Home Hub into firmware version 6.2.2.6 from Jarvisers Workshop BT Home Hub,
• the BT Home Hub firmware recovery tool,
• and finally, somewhere to get some decent kit and an ISP that won’t sell you such junk in the first place.

It did eventually acquiesce and start broadcasting – incredibly, the device does even support WPA2 in the latest firmware, though since BT routinely send firmware upgrades to it remotely, I won’t be surprised if it stops working again at some point. Not a system I’ll be recommending any time soon.

• FACT: Apple consistently spread FUD about how Windows is so much less stable and reliable than OS X.
• FACT: A large proportion of the PC problems I deal with are to do with Apple software being installed on it and breaking horribly.

The way I see it, there are only two logical reasons for this:

• REASON A: Apple are deliberately writing broken software for the PC in order to support their flawed argument that Windows is unreliable.
• REASON B: Apple are in fact completely incapable of writing software that works.

Right now I’m leaning heavily towards the former, but I hereby invite all Apple supporters to pick either one of these reasons and explain why that reason should convince me to ‘make the switch’.

UPDATE 00.21: More than 2 hours later and I’m still trying to figure out how to get this bloody iTunes install to work again. Anyone thinking of taking up my above invitation best be warned: I am not in the best of mindsets for hearing how fabulous Apple is right now.

So… I’ve chosen Vista Business, and you think I should ‘upgrade’ to the previous version?

I’m sure all the Vista-haters will cynically cry, “Hah, XP is an upgrade, n00b, because Vista is teh suck”, to which I reply, “Eat my ass, you cynical, whingeing, amateurs.” I’ve been running Vista since July, and I wouldn’t go back to XP. Fact.

High Contrast Mode is an accessibility feature in Windows that causes the desktop theme to switch off of Aero (or whatever is currently set) onto an almost completely black scheme with white text. It also disables the desktop wallpaper and changes the background colours of applications like Word to black, so it appears the user is typing white text onto black paper.

Despite repeated use of the Shift+Alt+PrtScrn shortcut, High Contrast Mode refused to turn off. Their desktop wallpaper did return, indicating that it was trying to switch out of High Contrast Mode, but not fully succeeding. Our students tend to have much of the Control Panel locked down (as I outlined above, the little bastards cherubs like to fiddle and break things), so the Control Panel applet to turn this off was not available to them, but even making it available and using the applet did not work.

I couldn’t find any mention of this via Google, and so it took me a little while to work out what was going on. I eventually traced this problem to an incorrect setting in the Registry. Here’s what my Vista laptop has set when High Contrast is activated:

[HKEY_CURRENT_USER\Control Panel\Accessibility\HighContrast]
"Flags"="126"
"High Contrast Scheme"=""
"Previous High Contrast Scheme MUI Value"=""
"Pre-High Contrast Scheme"="C:\Windows\resources\themes\Aero\Aero.msstyles"
"Pre-High Contrast Color"="NormalColor"
"Pre-High Contrast Size"="NormalSize"
"Pre-High Contrast Wallpaper"="C:\Users\JSCHLA~1\AppData\Local\Temp\BGInfo.bmp"

As you can see, this key records what the desktop scheme was set to before I switched to High Contrast Mode, in the “Pre-High Contrast Scheme” value.

Now let’s look at the registry of a user with the problem:

[HKEY_USERS\S-1-5-21-1708537768-2052111302-682003330-9422\Control Panel\Accessibility\HighContrast]
"Flags"="127"
"High Contrast Scheme"="High Contrast Black"
"Previous High Contrast Scheme MUI Value"="High Contrast Black"
"Previous High Contrast Scheme MUI Ptr"="@themeui.dll,-852"
"Pre-High Contrast Scheme"="@themeui.dll,-852"
"Pre-High Contrast Color"=""
"Pre-High Contrast Size"=""
"Pre-High Contrast Wallpaper"="C:\Users\BEN~1.KOL\AppData\Local\Temp\BGInfo.bmp"

As you can see there are a number of differences, but those of you paying attention will have immediately noticed the most pertinent discrepancy; this user’s “Pre-High Contrast Scheme”. Instead of the path to the Aero style file, it lists the previous scheme as “@themeui.dll,-852″. This is a direction to Windows to extract a string resource from a dll file and use that value as the theme. On an English Vista system, “@themeui.dll,-852″ contains the text string “High Contrast Black”. This means that when the user tries to deactivate High Contrast Mode, the scheme it reverts to is… the one used by High Contrast Mode.

How this happened is, so far, a mystery to me.

I corrected it using the following steps:

1. Ensure user is logged on and in ‘true’ High Contrast mode, by checking if their wallpaper appears. If there is no wallpaper, they are in High Contrast mode. If they are not, use the keyboard shortcut (Shift+Alt+PrtScrn) to switch it on.

2. Edit the user’s registry to set:

   HKEY_CURRENT_USER\Control Panel\Accessibility\HighContrast
   "Pre-High Contrast Scheme"="C:\Windows\resources\themes\Aero\Aero.msstyles"

   If RegEdit is prohibited for the user, either use Remote Registry, or create a shortcut to RegEdit on the desktop and use ‘Run as Administrator’, then set the same value under HKEY_USERS\SID-Of-User\Control Panel\Accessibility\HighContrast, substituting SID-Of-User for the SID of the user with the problem.

3. Use the keyboard shortcut again to switch out of High Contrast Mode. Theme should switch back to Aero.

4. Dance the happy dance of success (Optional).

5. Find child who turned High Contrast on as a joke and beat savagely with keyboard (Mandatory).

Hopefully that will help anyone with the same problem; I was getting surprising and unusual amount of stick from the kid’s teacher for “not fixing the problem” that was partly caused by a user, and partly (I presume) a bug in Vista. Such is life when you work IT Support; even if the user was completely responsible, it’s still your fault that it’s not fixed within minutes.

With that in mind, imagine my glee when I got the following email today.

Imagine now my complete lack of sympathy or surprise at this.

I’m sure some commentators will jump on this is ‘proving’ that subscription music services are simply not a viable business option. Let’s be clear; Virgin failed because they screwed the entire thing up. They had a working system which had some minor flaws, but instead of fixing the problems they relaunched an entirely different service which failed spectacularly and likely lost them most of their customers as a result. It’s difficult to recover from something like that. The only thing that baffles me is how they survived this long.

I remain convinced that music subscriptions are the way to go, all that has to happen is someone needs to sell it properly and have a system that works. It’s purely perception; many people baulk at the suggestion of not ‘owning’ their music (when in reality they don’t own it at all), yet they won’t bat an eyelid at paying £20 a month to rent television shows in the form of a cable or satellite subscription. The failure of any of the music subscription services to hit the mainstream is partly technical, as we’ve seen with Virgin, but it’s also a massive failure of marketing. As much as I hate to say it, I think if there is one company with the marketing muscle to pull it off, it’s Apple. If iTunes started such a service, it would be a success. I’m continually baffled as to what it is they think they have to lose by not doing so.