While Steve Smith’s answer is correct—in that blank spaces in a file/directory name need to be escaped (
\)—there is really a simpler way of dealing with someone telling you to ditch a file/directory in an attempt to fix a system: Just rename it or move it somewhere else!
The core problem with the advice you were given is the assumption that deleting a directory like that must happen via a command line in the Terminal. This is simply not the case.
The reality is while macOS hides the
~/Library/ directory by default, you can easily enable it in the Finder. Just open up a Finder window and go to your home directory—either manually or via Command+Shift+H—and then choose “View -> Show View Options” or hit Command+J.
At the very bottom of the list of options you’ll see “Show Library Folder.” Just check that off—and even push “Use as Defaults” if you wish—and you will have instant Finder access to the
~/Library/ directory. Screenshot below for reference:
Or, just open up a Terminal and type:
And that will literally open open the
~/Library/ directory and allow you to poke around in there.
With that done, just rename
~/Library/Application\ Support/ to something like
Grammarly-BACKUP/ and then launch the application again. For all intents and purposes renaming a directory like that will make it “invisible” to the application. Or you could even just drag that
Grammarly/ directory to the Desktop—or even Trash—and do the same. Remember, computers don’t know where things are if you move or rename files.