Forum Discussion
Can't remove file association to STL files
Hello, I work with STL files in multiple programs, and after installing a new one, it automatically assigned itself as the default for STL files. I do not want to assign an alternative default, I want there to be NO default, however even after reseting all default apps, and deleting UserChoice in the registry editor under
Computer\HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.stl\UserChoiceLatest stl files still automatically open with this new program (chitubox if anyone's curious). How do I address this
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Windows 11’s Default apps interface lets you replace the handler for a file type, but it does not offer a “no application” choice once an association exists. Resetting defaults restores Microsoft-recommended handlers; it does not clear extensions, and manually deleting UserChoice registry entries is not a supported method. Check CHITUBOX settings and disable registration of STL files. Go to Settings > Apps > Default apps, search for .stl, and assign the program you prefer. If you want no installed handler, uninstall CHITUBOX, restart, and test by double-clicking an STL file. Reinstall it only after confirming its installer does not reclaim the extension. If the association remains after uninstalling, use Settings > Apps > Installed apps to repair or remove the registering application, then restart Explorer. Avoid further registry edits because Windows can recreate protected associations. Windows has no supported UI workflow that guarantees a known extension remains permanently unassociated.
