For a Brother printer, the message "Toner Error" is normally caused by the improper installation of the drum and/or toner cartridge, or the printer will not recognize the toner. To prevent the printer showing “error” or “not recognize” when installing a toner cartridge, follow the steps listed below which was retrieved from FixYa.com, a technical support and troubleshooting site for consumers with computer related problems:

1. Confirm that you are using Genuine Brother Cartridges. Brother strongly recommends that you use only Genuine Brother Brand replacement toner cartridges. Incompatible toner cartridges may damage the printer.

2. Make sure that you are using the correct drum and toner cartridge for your printer. Some cartridges can look similar to Brother Cartridges. Authenticate the part number before using the cartridge.

3. Make sure that the cartridge is not damaged. Remove the toner cartridge by carrying out the following steps:

a) Push the cover release button and then open the front cover.

b) Remove the old drum device and toner cartridge unit. Place it on paper to prevent toner splatter.

c) Hold lock lever down on the right and pull the toner cartridge out of the drum unit.

d) Check the toner cartridge for any broken or missing components. If you find damage, you will have to replace the cartridge

4. If the toner cartridge is not damaged, reinstall it into the drum unit. If it was damaged, get a new toner cartridge and reinstall it into the drum unit.

5. Reset the drum/toner unit into the machine and then close the front cover.

6. If the message "Toner Error' continues to appear on the display, unplug the printer and then open the front cover and remove the drum and toner unit.

7. Check inside where the drum was located. On the left side wall, check for a small, black plastic lever/actuator.

8. Check the actuator/lever to see if it is stuck. The actuator/lever is spring loaded and needs to move back and spring forward to operate properly.

If the lever does not move, spring back, or is missing, and your machine is within warranty, you can locate a Brother Authorized Service Center (ASC) in your area or contact Brother Customer Service by calling 1-877-Brother (1-877-276-8437)

If the lever moves freely and springs back, continue to Step 9.

9. Reinstall the drum and toner unit, close the front cover and then plug the printer back in.

* Source: www.fixya.com

Unfortunately, things happen from time to time that will result in computer related problems such as a toner error on a Brother printer. However, you do not have to panic. There is technical support available. If you are uncomfortable with attempting to fix the problem yourself, it would be best to contact customer technical support at Brother