As a result of moving from a WinXP box that didn't have a drive C: to a new Win7 64-bit Pro box with Laplink PCmover Professional doing its best to move applications intact, I have a few lingering issues with abandoned references to the old drive E:. I've eradicated most of them by persistent uninstall and reinstall of apps that cared (and simply discarding some that couldn't be made to see sense). Overall, PCmover made the transition pretty painless, aside from a few quirks like this one.

A search of the registry for references to E: has turned up a handful of entries under HKEY_CLASSES_ROOT\Installer\Assemblies where each key is named something like HKEY_CLASSES_ROOT\Installer\Assemblies\e:|Program Files|Reference Assemblies|Microsoft|Framework|v3.5|Microsoft.Build.Conversion.v3.5.dll in which the reference to the old system drive is pretty clear.

Is it safe to simply delete these?

Does anyone know what they signify?

The values they contain are oddly named, and appear to include arbitrary content with no obvious meaning.


You can probably just leave those items there. That is what I would reccomend doing.

--EDIT-- As further clarification, if all the software that originally placed those registry keys have been reinstalled, then you probably have nothing to worry about. the example that you provided refers to an assembly that MS Visual Studio and it's derivatives use to convert projects between Visual Studio versions. If nothing is expecting to find that registry key, then it is virtually harmless.

HKEY_CLASSES_ROOT (HKCR) is where information about file associations is stored (see this MSDN article for more information).

If you really don't want them there, then you could probably delete them. However, I do suggest caution, as this registry location also ties into the .Net GAC and if you remove references (even to files that are not there) then some software may become unstable or non-functional. Always, Always, Always backup your registry hives somehow before you do any editing.

  • IMHO, HKCR is used for too many purposes and supports too much backward compatibility. It is a shame that they keep sticking new things in there. I'd agree that as long as those entries are not enumerated and the matching disk locations searched, then I should not be harmed.... – RBerteig Feb 23 '11 at 2:55

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