LIVESCRIBE 3 - Ink cartridge falls out of Livescribe 3 smartpen or does not appear when smartpen is on

Why won't my ink cartridge stay in the Livescribe 3 smartpen or why does it disappear when I insert it while the pen is on?

After removing an ink cartridge in order to replace it, if the ink cartridge you insert in the Livescribe 3 smartpen falls out or disappears:

If connected, disconnect the pen from the USB charging cable.
Verify the smartpen LED is on (green or blue). If it is not, turn on the pen by twisting the power ring.

If the ink cartridge initially fell out, insert the ink cartridge again until it locks in place.

If the ink cartridge initially disappeared, hold the pen horizontally and make a whip-like action towards the floor (so that you don't hit anyone with the ink). The cartridge should be forced out of the pen and drop to the floor.

If the ink cartridge still falls out, or you had to force it out, it is likely that the cartridge was made for wifi/Echo/Pulse smartpens as those cartridges are shorter than Livescribe 3 cartridges and are not compatible with Livescribe 3 smartpens.

For reference, Livescribe 3 ink cartridges are sold in this package:

Livescribe Support

Wifi/Echo/Pulse ink cartridges are sold in this package:

Livescribe Support