FreeStyle Libre Sensor Error — No Reading Fix (Libre 2 & 3)

Hello. If your FreeStyle Libre 2 or Libre 3 is displaying an error, a blocked signal, or no glucose reading, this guide walks through the most common causes and fixes. Step 1: Understand the sensor reading modes for Libre 2 and Libre 3. The FreeStyle Libre 2 requires you to scan the sensor with your phone or reader every 8 hours to avoid data gaps. It does not transmit readings continuously — you must actively scan. The Libre 3 does transmit readings continuously to the LibreLink app every minute, but requires Bluetooth to stay connected. Step 2: For Libre 2 — check your scan technique. Hold your phone or reader within 1 to 4 centimeters of the sensor. You should hear a beep and see a reading within a second or two. If scanning does not work, remove any phone case that might be blocking NFC, as thick or metallic cases can prevent scanning. Step 3: For Libre 3 — check Bluetooth connection in the LibreLink app. Open the LibreLink app and look for the Bluetooth connection indicator. If the app shows "sensor not found" or the Bluetooth icon has an X, toggle Bluetooth off and back on in your phone settings, then reopen the app. Step 4: Wait through the 60-minute warm-up period. The FreeStyle Libre 2 has a 60-minute warm-up after application. The Libre 3 also requires a 60-minute warm-up. During this time, you cannot get a reading. The LibreLink app will show a countdown. Do not remove the sensor during warm-up. Step 5: Check for a "Blocked" or error code on the Libre 2 reader. If the reader displays a blocked signal icon, there may be a temporary interference. Move away from electronic devices and try scanning again. A "Check Blood Glucose" or checkered flag icon means the sensor is asking you to confirm your reading with a fingerstick before taking action. Step 6: For consistent Libre 3 dropouts — check Android battery settings. Android phones often stop Bluetooth background processes to save battery. Go to Settings → Battery → App Optimization, find LibreLink, and disable battery optimization for it. This is the most common reason Libre 3 readings stop arriving. Step 7: If the sensor shows "Sensor Failed" or does not recover within 3 hours — contact Abbott. Call Abbott Diabetes Care at 1-855-632-8658. FreeStyle Libre sensors are covered by Abbott's guarantee. Have the sensor's lot number ready from the packaging. Replacements are shipped free. Step 8: Bridge with fingersticks. During any sensor error, check blood glucose with a fingerstick meter for all treatment decisions. Do not treat high or low readings based on a sensor that is displaying an error. Still need help? Find a CGM provider near you →