How do I open Multiple NotePad files from a folder?in Windows 10 Selecting all and then pressing Enter won't work, Selecting all and then trying to get an option of open by right clicking mouse button don't work.
There is an arbitrary limit of 15 selected files in the context-menu, as explained in this Microsoft article: Context menus are shortened when more than 15 files are selected.
The solution is to use
regedit and navigate to the key:
On the right-hand pane, change the value of the item
MultipleInvokePromptMinimum to a limit that suits you better.
If the item does not exist, create it as DWORD 32-bit.
The change takes place right away without a logoff or restart. However, I would be careful with setting this to a too big value.