File Regedit Ff

Run in Command Prompt as admin:

dism /online /cleanup-image /restorehealth
sfc /scannow

Then reset default apps via Settings → Apps → Default Apps → Reset. file regedit ff

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Mozilla\Mozilla Firefox\*
"DisableAppUpdate"=dword:00000001
]

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet\FIREFOX.EXE\Capabilities]
"ApplicationName"="Mozilla Firefox"
"ApplicationDescription"="Web Browser"

Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\firefoxURL]
@="URL:Firefox Protocol"
"URL Protocol"=""
[HKEY_CLASSES_ROOT\firefoxURL\shell\open\command]
@="\"C:\\Program Files\\Mozilla Firefox\\firefox.exe\" \"%1\""

If you manage multiple PCs, you can file a .reg script that sets Firefox policies. Run in Command Prompt as admin: dism /online

Example: Block Firefox updates via Registry Then reset default apps via Settings → Apps

Save the following as set-fffile.reg and double-click to import (edit paths if needed):

Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\.ff]
@="FFFile"
[HKEY_CLASSES_ROOT\FFFile]
@="FF Document"
[HKEY_CLASSES_ROOT\FFFile\DefaultIcon]
@="C:\\Windows\\System32\\notepad.exe,0"
[HKEY_CLASSES_ROOT\FFFile\shell\open\command]
@="\"C:\\Windows\\System32\\notepad.exe\" \"%1\""
[HKEY_CLASSES_ROOT\FFFile\shell\OpenWithNotepad]
@="Open with Notepad"
[HKEY_CLASSES_ROOT\FFFile\shell\OpenWithNotepad\command]
@="\"C:\\Windows\\System32\\notepad.exe\" \"%1\""

Warning: Incorrect registry editing can break Windows or apps.

Note: You may need to create the Mozilla\Firefox folder structure under Policies.