Why does Liftmaster say not to use LED bulbs?

LiftMaster does not say never to use LED bulbs, but it does caution against using standard, non-compatible LED bulbs because many cheap LEDs cause radio frequency interference that interferes with the garage door opener remote controls. The issue is not the LED light emission itself but the driver electronics inside the bulb that converts AC power to DC. Poorly shielded drivers can emit electromagnetic noise in the 300 to 400 megahertz frequency range, which is exactly the same frequency band that LiftMaster Security+ and Security+ 2.0 remotes use to communicate with the opener. When the opener light turns on, that noise can blind the receiver in the motor head, causing your remote range to drop from 50 to 100 feet down to just a few feet, or to not work at all until the light turns off automatically. This is why LiftMaster's manuals warn that some LED bulbs may cause interference and recommend using bulbs specifically tested and labeled as garage door opener compatible. LiftMaster now sells its own A19 LED bulbs that are shielded, vibration resistant, and rated for cold garages to avoid this problem. Using a high-quality, FCC-compliant, garage door rated LED avoids the interference issue entirely.