reset SMC , also uncheck and check each setting on the cursor
- Shut down the computer.
- Plug in the MagSafe power adapter to a power source, connecting it to the Mac if its not already connected.
- On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.
- Release all the keys and the power button at the same time.
- Press the power button to turn on the computer.
Note: The LED on the MagSafe power adapter may change states or temporarily turn off when you reset the SMC.
I do not use Excel however there is a discussion here about that very topic:
I find no indication of change potential on the cursor in Excel by their indications.
"That's the default cursor when located in the worksheet."