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© Rakhesh Sasidharan


MSI, MST, and disabling auto-healing/ self-repair/ “please wait while Windows configures” messages for certain applications

This issue had be irritated for a week. Finally, thanks to this blog post I think I solved it. Fingers crossed. Bloody Darwin descriptors! :)

So what was the issue? I setup Citrix XenApp for Office 2010, FileSite, and some more applications. The first time I’d launch Outlook 2010 and go to FileSite it would do this initial configuring:

Fair enough – I figure it has to do some initial registry key and folder stuff. I can live with that.This initial configuring is not too harmful either except for a bit of delay to the user. Via GPOs I have pushed out registry keys to set my default library and also tweak some FileSite settings, and this initial configuring does not blow away any of that.

Next I launch Word or Excel and they work happily with no initial configuring. However, sometimes – and this seems to be either when I launch Word or Excel soon after I click Outlook, or when I open one of these via Outlook (like I double click on an attachment), or sometimes just randomly – Word and Excel too do this initial configuring. And they blow up all my GPO pushed out registry settings and that irritates the hell out of me!

Something was causing these two to randomly trigger a repair of FileSite and I had no idea what. I figure it must be some registry key or file that is missing and that’s causing Word or Excel to repair FileSite, but I couldn’t find anything. I spent some time with Citrix UPM doing trial and error, checking to see if I was excluding some important folder, but couldn’t find anything. (I know should have just used SysInternals Procmon to find out what was triggering this I guess, but I felt lazy going that route). Then I decided to try and explore the MSI/ MST file itself and see what I can learn.

I used Orca to view the MSI file and apply the MST transforms to see what was happening. Truth be told, while it was good to understand the structure and what one can do, it didn’t really get me anywhere. From the Application logs on my machine I could see messages like these:

And using Orca I was able to track down these features and components and see what files or registry keys they might be looking for. My hunch was that possibly the file or registry key looked for by these components were missing and that was triggering a self-repair for FileSite. But all those keys and files were present on my machine as far as I could tell, so that was a dead-end.

Here’s an amazing article on features and components and how the self-repair feature is triggered when a file it requires is missing. And here’s another amazing post from StackOverflow that generally goes into the topic of self-repair.

Every time you launch an advertised shortcut (essentially a special shortcut that points to a Windows Installer feature and not directly to a file), Windows Installer will verify the installation by checking the “component key paths” for your product. If a discrepancy is found, a repair is triggered to correct the incomplete installation. The “component key paths” are the “key files” specified for the components inside your MSI – there is one per component. Self-repair can also be initiated by someone instantiating a COM server (or attempting to), someone activating a file via its file extension or MIME registration, and a few other ways.

The impression I got from both articles is that there are entry points to an application and it is possible to tell Windows to do an integrity check when accessing the application via these entry points and if the check fails then do a self-repair. I am not sure if the “Please wait while Windows configures …” window is part of the integrity check or self-repair, but considering it was making changes I am sure it was triggering the self-repair anyways. There are a lot of entry points, from the advertised shortcuts mentioned above (see this article for an example) to activating a repair when doing an action such as opening a document or print.

(As an aside, an MSI/ MST has an ALLUSERS property that determines if it is installed per-machine or per-user or both).

While reading on this topic I also came across this informative article on COM and registry stuff. It isn’t directly relevant to self-repair but has an indirect reference. Here’s some bullet points (note: the actual article has a lot more stuff):

  • COM objects (DLLs? also object classes?) are identified by a GUID. This is called a Class Identifier (ClassID). These are stored under HKEY_CLASSES_ROOT\CLSID. In my machine for instance C:\Windows\system32\oleaut32.dll has a ClassID of {0000002F-0000-0000-C000-000000000046} and can be found under HKEY_CLASSES_ROOT\CLSID\{0000002F-0000-0000-C000-000000000046}.
  • Within the CLSID key in the registry there exists a key called InprocServer32 that points to the actual DLL referenced by the ClassID.
  • Since ClassIDs are GUIDs and hence difficult to remember, we also have Programmatic Identifiers (ProgIDs) that are pointers to these. (It’s like DNS basically. The ProgID is the DNS name; ClassID is the IP address). ProgIDs are stored under HKEY_CLASSES_ROOT.

To take an example from my machine: HKEY_CLASSES_ROOT\Citrix.ICAClient is the ProgID for the Citrix ICA client. Within this HKEY_CLASSES_ROOT\Citrix.ICAClient\CLSID gives me its ClassID which is {238F6F83-B8B4-11CF-8771-00A024541EE3}. I can find this ClassID under HKEY_CLASSES_ROOT\Wow6432Node\CLSID\{238F6F83-B8B4-11CF-8771-00A024541EE3} (notice it can also be under Wow6432Node coz my machine is 64-bit).  In this HKEY_CLASSES_ROOT\Wow6432Node\CLSID\{238F6F83-B8B4-11CF-8771-00A024541EE3}\InprocServer32 points to C:\Program Files (x86)\Citrix\ICA Client\wfica.ocx.

Elsewhere in my machine I also have HKEY_CLASSES_ROOT\MIME\Database\Content Type\application/x-ica which has a CLSID value pointing to the above. So this is how MIME types are associated with the OCX file above (whatever that does).

The above article is the first time I came across the Darwin Descriptor. It was briefly mentioned as something that could be in the InprocServer32; but more on that soon.

Searching more on these topics and self-repair I came across this article. I think I was searching for entry points that trigger self-repair and by now had an idea that self-repair could probably be associated with the registry keys I mentioned above. I’d like to excerpt this FAQ from the same article (emphasis mine):

Q1: Who decides what components are “required”, and what is “intact”?
A1: The author of the installation package. Quite often, he simply follows the wizard in his MSI-authoring product without giving full consideration to what is really required, what is not, what should stay intact and what should not. “Intact” means that the specified file or registry key does exist. The contents of the file or the value of the registry key is allowed to change, so if it is changed, this does not make the installation “not intact”.  But if it is deleted, then the installation becomes “not intact”.

Q2: Why does Windows Installer repair product A if I launched product B?
A2: Very often, product A installs various hooks in the system, and they are used by all applications, including product B. For example, Adobe Reader installs certain extensions in Windows Explorer, which allows full-text searching in PDF files – i.e. you can search in Windows Explorer for all files containing a certain phrase, and Explorer will be able to find that phrase in PDF files – thanks to the extension installed by Adobe Reader. Another function of the extension is generating thumbnails of PDF files for Windows Explorer. This means that whenever you open a folder in Windows Explorer, Adobe Reader’s extension gets activated.  And since Adobe Reader has been installed with resiliency, this means that whenever you open a folder, the system verifies if the Adobe Reader extension is intact. If it’s not, then it will launch the self-repair process.

Q3: But why is it launched every time?
A3: Because it either fails to repair, or because it’s trying to repair a file that the application itself later removes during its regular operation. Such files should not be included in resiliency, but nothing prevents the author from including them; and if the author’s InstallShield or Wise warns them that a certain component has no resiliency information (by highlighting components with no keypath), the author will often blindly comply and create keypaths, even when in fact they are not required.

From this article I came across another article by the same author and here he talks about the Darwin Descriptor. Basically, the Windows installer used to be called Darwin and you can have registry keys that look like garbage but which actually tell it to go and do an integrity check and do self-repair if required. I’d suggest going and reading that article as the author explains it clearly but here’s how it helped me.

Let’s start with one of the Application log errors:

Using Orca  I found the component {86BFF64E-1771-4EF1-991C-C6A99F9690A6}.

By the way, Orca calls it ComponentID, so the Component as far as Orca is concerned is “WSO27AddinsShim.dll.471442DE_0EAA_4BBD_B726_5348144025DB”. Just for kicks, note that it points to a directory called “INSTALLDIR.471442DE_0EAA_4BBD_B726_5348144025DB”.

In the Directory table of the MSI I can find that this points to a “INSTALLDIR”, which in turn is a sub-folder of “WORKSITE”, which in turn is a sub-folder of “INTERWOVEN”, which in-turn is in the Program Files folder. So basically “INSTALLDIR.471442DE_0EAA_4BBD_B726_5348144025DB” points to “Program Files\Interwoven\WorkSite”.

I couldn’t capture it in the above screenshot, but that row also contains a column called KeyPath with the following: “wso27addinsshim.dll.471442DE_0EAA_4BBD_B726_5348144025DB”. Looking at the File table I can find that this points to a file called “WSO27A~1.DLL” (the 8dot3 file name) or “WSO27AddinsShim.dll” (the long name) of version and size 123144 bytes – which I confirmed does exist in the directory path above.

OK, so as of now I have identified the component that is giving an error during integrity check and confirmed that the file it refers to actually exists. So there’s no reason for the integrity check to fail, and anyways if it is failing I can convince myself that it is safe to disable it somehow because the file in question does exist. How do I disable that? For this I went to the Registry table in Orca and found the entries created by the “WSO27AddinsShim.dll.471442DE_0EAA_4BBD_B726_5348144025DB” component. Among the many entries it was creating I found one with the CLSID: CLSID\{37a96034-eb52-4509-96a2-8aee5ea2c093}\InprocServer32. So I went over to HKEY_CLASSES_ROOT\Wow6432Node\CLSID\{37a96034-eb52-4509-96a2-8aee5ea2c093}\InprocServer32 and found a value called InprocServer32 with the following: DC3E4j?Pc8'Y%mIPIlQXFileSite_x86>BzW5J%'5q?se1OG%XntL.

From the article above I knew that I knew that this gibberish was basically telling Windows to do an integrity check and repair of the FileSite_x86 feature (and if you read one of the articles I linked to earlier a feature contains other features and components, so by telling Windows to do an integrity check on the FileSite_x86 feature it was basically triggering the integrity check and repair of a whole other bunch of components – see screenshot below from the FeatureComponents table).

Anyhow, to fix this I went ahead and deleted the InprocServer32 value. I did the same for the CLSID of the other component that was giving an error, and with these two fixes I was effectively able to stop the integrity check and self-repair for FileSite from happening when I launched Outlook, Word, or Excel. It remains to be seen if I encounter new issues because I missed out on adding any files or registry keys expected by FileSite that were previously being added by the self-repair, but we’ll cross that bridge when it comes. :)