Windows Vista file type and file extension associations may be corrupted, broken and go haywire, causing files with some extensions cannot be opened properly. For example, some third party programs may wrongly set or assign file associations for extensions that not supposed to have a default program such as .exe, .com, .sys, .lnk, folder, directory, drive etc. (actually these special system files has unique associations which is not supposed to be another programs, so that Windows know to handle them accordingly).
Some programs that known to cause such problem including Lavasoft Ad-Aware SE with “Lock executable file associations” option enabled in Ad-Watch via automatic setting, which blocks registry changes related to file associations when new software application is installed or updated. Another possibly problematic app is dTools, which may delete or remove associated default program and icon for .exe, .sys, .scr, .rll, .pko, .pif, .ocx, .wmdb, .wsp, .xmp, .tpl and other extension types. Sometimes, user may accidentally unassociate or delete the file association too, or assign default apps for file extension or file type such as shortcut with .lnk to a wrong program when forget to uncheck “Always use this program to open this type of file” option.
When a file type association for an extension is deleted or not found, the icon for the file type becomes blank in the shape of empty white paper. And when user double clicks or run the affected file of the kind of extension type, system will prompt user with a “Open With” dialog to find a program to open the file with.
The problem is especially worse when the file association for executable with .exe extensions is broken, causing programs such as Adobe Reader, Internet Explorer, Notepad, System Restore, Microsoft Office Word, Excel, PowerPoint, and even Registry Editor (which is necessary to fix the invalid file association problem) cannot be started, and unable to launch or execute.
Windows Vista basic file extension Set Association management interface cannot reset and fix the corrupted or invalid file association back to factory default, or at least back to a workable state. As a workaround, user can try to manually remove the user-choice file association to restore back to Windows default file type and extension association.
If the manual deletion of user customized file association does not work, or want to direct yet simple fix for the file type and file extension association problem, winhelponline.com has provided a few registry files that fix and reset several common file associations in Windows Vista back to its original default as if right after fresh installation.
The file association fixes for the following file extensions are available, which can be downloaded in ZIP format which contains a .reg file. Execute the registration entries file to merge the registry keys and values to replace and reset the existing system registry.
For user who wants all the file association fixes, here’s a compressed zip file
vista_extfix.zip (no longer available) that contains all of the individual file extension association fixes above.
Note that to apply the registration entries file (the .reg file downloaded), user must right click on the .reg file and select “Run as Administrator” to apply the file association fix for the respective file type and extension.