WiX: Reasonable way to “fix” original version uninstall issue with new version installer

Question

I created a WiX-based installer back in the WiX 3.5 days. The documentation then was even worse than it is now. To make matters worse, it was my first installer—so I didn't do everything right.

Some background: the installer installed two applications and a driver (each of these were a separate feature consisting of one or more components). One of the applications in question is a vendor-proprietary device configuration application written in VB6. Since it's a VB6 application, it uses the libraries comctl32.ocx and tabctl32.ocx.

The crux of the problem is that I didn't see these two libraries in the %windir%\System32 folder on Windows Vista (and/or Windows XP? I don't remember, it's been years since I first wrote this installer). So I thought I needed to install these two libraries along with all of their requisite COM registry entries. (I ended up installing the COM libraries in my application's folder—as you would for a private assembly, but registered them globally in HKLM.) As much as I read about things when creating the first installer, I never once came across the fact that, as of Windows XP, COM components could be installed side-by-side. (And even so, why didn't I use the MSI tables Clsid, ProgId, etc.—which granted, today, is frowned upon, but it would at least have been more correct than what I did? But I digress; what's done is done in MSI land.) Anyway, when creating the original installer, I used the following WiX markup for creating the COM registry values:

<RegistryValue ... Action="write" />

I also should mention that at the time, I had not come across any sort of 'Component Rules 101' kind of documentation as I have this time around. So, this MSI does not follow the component rules. The MSI contained one component for each COM library and its associated registry values with the COM library being the KeyPath of its component.

The question is, if the registry keys/values existed prior to my original MSI running and installing the first version of my product, will uninstallation cause these keys/values to be removed from the system? (I assume these keys/values were created during Windows setup—so are they already reference counted?) I don't want to possibly break other applications on a users' system that relies on those libraries.

If the answer to the above is yes, then my current plan to rectify the situation is:

• Author a new MSI as a <MajorUpgrade />—afterall, I am performing an upgrade.
• Provide the COM registry entries that were in the original installer for the comctl32.ocx and tabctl32.ocx COM libraries—I'm guessing that I would need to do this with a CA (or multiple CA's) so that they don't get removed again on the next upgrade. I see one of two ways of accomplishing this:
  1. Directly create the registry entries taking care to ensure the values match those of a fresh windows installation (appropriate to the version of OS on which the installer is executing)
  2. Dynamically add the registry entries to be created to the MSI Registry table (which if I understand correctly, isn't tracked by windows installer in terms of uninstallation?)

If previously existing registry keys overwritten by MSI are removed on uninstallation, then:

1. Is my proposed solution acceptable?
2. Which of the two options for replacing the removed registry entries is best?
3. If neither of those two options are acceptable, does anyone have any other suggestions on how I might rectify the situation so as not to break other applications that (may) rely on the libraries in question?

Answer 1

It was a long read but I think this is what you are looking for:

ICE09

To quote the beer commercials.... I don't always install files in the SystemFolder but when I do, I make them permanent.

Answer 2

First, thanks to Christopher Painter above for responding to my question; though, it's not really an answer in the sense that I'm looking for—fixing an existing installer that's "out in the wild". Though, in his last comment about a minor upgrade, that might work for some people.

Next, thanks to Aaron Stebner who responded to my e-mail requesting guidance on this same issue. His advice is to author a MSI component which has no ID. By authoring such a component into a MSI, the component is not tracked by MSI; essentially, it becomes a permanent, uninstallable component. This might work in this situation, if it were completely necessary.

However, after doing some research, I believe that there isn't much risk to damaging a user's system by removing the registry entries I outlined above.

I loaded a fresh copy of Windows XP SP3 and Windows Vista SP1 into a virtual machine. Out of the box, neither of these versions of Windows have the COM components in question registered in anyway in the Windows registry. This makes sense, since from Windows XP onward, there has been registry-free COM registration. This also continues to be the case for Windows 8.1—again, this was expected.

The worst that could happen if these registry keys are uninstalled is that some other older piece of software on a machine that relied on such registry entries could end up broken (e.g. this software is from the late-90's to early 2000's era and used a non-MSI installer and/or installed the COM libraries globally—which they shouldn't have done in the first place—just like I shouldn't have done in the first place ;) ). At that point, the user can either re-register the COM libraries using regsvr32.exe or repair/reinstall the application in question. The likelihood of such applications existing are slim to none in this day and age.