When you insert a cassette, the meter reads the RFID tag, which contains the exact expiration date and a "use-by" period (usually 90 days once opened). The 90-Day Lock:
Even if the printed date on the box hasn't passed, the meter starts a 90-day countdown the moment you first insert the cassette. Once that 90-day internal clock hits zero, the meter will display an (Cassette Expired) and refuse to take a reading. Data Mismatch: accu chek mobile cassette expired hack
(removing batteries and holding the power button) may clear the meter's memory, but it does reset the chip inside the cassette itself. Accu-Chek.co.uk Critical Safety Warning Accu-Chek Mobile test cassette When you insert a cassette, the meter reads