I heard from a customer who received an error message while trying to install Visual Studio 2005. The dialog box had the title Document Explorer and the text Unknown error. The customer pressed OK and the dialog did not cause setup to fail. However, the same error appeared again when attempting to launch the VS IDE, and pressing OK caused the IDE to exit and be unusable.
It turns out this error can be caused by a product named Icon Packager being installed on the system. The customer found this MSDN Forum post that described his scenario, and the workaround listed there fixed this error. I wanted to post a link to it on my blog as well to hopefully make it easier for others to find it.
The workaround is to do one of the following:
- Uninstall the Icon Packager product
- Unregister one of the Icon Packager DLLs by running regsvr32.exe /u iprepair.dll