ROVguy:
After creating a portable folder within the IDE installation folder on C drive the IDE doesn't boot at all. You see the IDE pops open for a moment and then disappears.
You must have the Arduino IDE installed to the Program Files (x86) folder. Windows 10 is very restrictive of changes to that folder. When the Arduino IDE starts, it's trying to create a sketchbook folder under the portable folder but Windows blocks that folder creation, which causes the Arduino IDE startup to fail.