Hi Mathew,
- What exactly happens whe you try to add the apps to the T1-84 Calculator? Do you get any error messages?
- Do you face any connectivity issue with the device?
- Was it working before?
It looks we need to change settings in the device in-order to save or add the apps.
You may refer this article from Texas Instruments:
Step by Step Instructions for downloading Calculator Software Applications (Apps) and Operating Systems (OS) onto TI Graphing Calculators.
http://education.ti.com/en/us/product-resources/download
Also refer:
Troubleshooting Error Messages or Unexpected Results
If the I would also suggest you to contact Texas Instruments for further assistance.
http://education.ti.com/en/us/customer-support/support
Hope this information helps. Reply with the status so that we could help you further.