Solved Notepad jumplist not working after Windows update

If the open folder is entirely missing under txtfilelegacy\shell, you need to create it manually. [1]
During major updates like 25H2, Windows strips these legacy shell verbs to break the system integration of classic apps and force the modern UWP container to take over. When the taskbar shell processes a left-click, it checks this exact missing location; finding nothing, the command fails.
Creating the missing folders directly inside the registry will fix the structural link.

Step 1: Create the Missing Keys
1.    In the Registry Editor, navigate to:
HKEY_CLASSES_ROOT\txtfilelegacy\shell
2.    Right-click the shell folder, select New, and click Key.
3.    Name this new key exactly open.
4.    Right-click your newly created open folder, select New, and click Key.
5.    Name this sub-key exactly command. [1, 2, 3]
Step 2: Set the Execution Path
1.    Left-click on the new command folder to highlight it.
2.    In the right-hand panel, double-click the (Default) value.
3.    Change the Value Data to exactly include the quotation marks:
"C:\Windows\System32\notepad.exe" "%1"
4.    Click OK

Step 1: Explicitly Direct the .txt Extension Map
1.    Press Win + R, type regedit, and press Enter. [1, 2, 3]
2.    Navigate to this exact path:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.txt
3.    Click the arrow to expand the .txt folder. If you see a sub-folder inside named UserChoice, right-click it and select Delete.
4.    Now, click on the OpenWithProgids folder under .txt.
5.    On the right-hand panel, look at the list of items.
o    If you see txtfilelegacy, double-click it and ensure its Value data is set to 0 (zero).
o    If you do not see txtfilelegacy, right-click empty space on the right, select New > Binary Value, name it exactly txtfilelegacy, and leave the value blank.
o    Delete any other modern strings listed there (such as AppX keys or Microsoft.WindowsNotepad).