This worked for me:
The machine turns on Mirror mode by itself, how can I correct this?
1. Turn Off the machine.
2. Open the tape compartment cover and remove the tape cassette from the machine.
3. Re-install the tape cassette back into the tape compartment. Push down on top of the cassette; ensure that it is seated firmly in the tape compartment and close the cover completely.
4. Reset the machine.
Note: All text, settings and stored files will be cleared.
a. Hold down the Shift and R keys.
b. While holding down the Shift and R keys, press the On/Off key once.
c. Release the Shift and R keys.
5. Try printing a label.
6. If the problem appears, try another Brother TZe tape cassette.
If the problem persists, your machine may require service.
The machine has a one year limited exchange warranty. If the machine is in warranty, call Brother Customer Service at 1-877-Brother (1-877-276-8437) for warranty options.
If the machine is out of warranty, contact a Brother Authorized Service Center for repair by clicking on the link below:http://www.brother-usa.com/service/default.aspx