my schedule keeps disappearing or resetting on its own. i set it and a day later it's gone.

Diagnosis

The disappearing schedule on the Honeywell Home RTH6580WF is typically caused by a "sync conflict" between the local device memory and the cloud server. This model uses a hybrid storage system where the schedule is mirrored across the physical thermostat, the Total Connect Comfort (TCC) app, and the web portal. When a user makes a change on the wall unit and then later modifies a setting via the app, the server may trigger a "push" update that overwrites the local memory with an older or blank configuration, effectively wiping your custom settings. Another common culprit is a failing backup battery or unstable 24V power coming from the C-wire. If the thermostat experiences a momentary power dip (brownout), the volatile memory holding the current schedule can corrupt. Because the RTH6580WF relies on a constant connection to maintain its cloud-synced state, any interruption during a "save" cycle can result in the device reverting to the factory default "5-2" or "7-day" blank template. You can confirm this by checking if the "WiFi" icon on the display flashes or disappears shortly before the schedule resets.

How to Fix It

To resolve this, you must establish a "Single Source of Truth" to stop the conflicting sync cycles. The most stable way to program this unit is via the web portal rather than the wall unit or the mobile app.

1. Perform a Hard Reset: Turn off the power to your HVAC system at the breaker for 30 seconds, then turn it back on to clear the temporary cache.
2. Clear Existing Data: On the thermostat screen, press Menu, navigate to Schedule, and select Clear All. Confirm the deletion to ensure no ghost settings remain in the local memory.
3. Log into the Total Connect Comfort web portal via a desktop browser (not the app). This is the master server for the RTH6580WF.
4. Navigate to the Settings tab and select Schedule.
5. Input your desired temperatures for the four periods: Wake, Away, Home, and Sleep. Ensure you explicitly save each day of the week.
6. Once saved on the web portal, go to the physical thermostat. Wait 5-10 minutes for the "cloud sync" to push the data to the device. You should see the new temperatures appear automatically on the screen.
7. Avoid touching the Schedule menu on the physical wall unit for 48 hours to ensure the server-side settings have fully locked in.

If That Didn't Work

• Check for C-Wire Stability: If the schedule continues to vanish, your thermostat may be power-cycling. Remove the faceplate from the wall and ensure the blue (or black) C-wire is seated firmly in the terminal. If you are using a "Power Extender Kit" (PEK), ensure the wiring at the furnace control board is tight; a loose wire here causes intermittent power loss that wipes the memory.
• Update the Firmware: Ensure your device is running the latest firmware. While there is no "Update" button, you can force a check by removing the device from your TCC account and re-adding it via the "Add Device" process in the app. This forces the thermostat to ping the server for the latest software version.
• Verify "Hold" Settings: Check if the thermostat is stuck in a "Permanent Hold" mode. If a user accidentally presses Hold on the wall unit, it will appear as though the schedule is gone because the unit is ignoring the programmed time blocks. Press Run Schedule to override any active holds.
• Test the Backup Battery: If your model has a coin-cell backup battery behind the faceplate, replace it with a fresh CR2032. A dead backup battery cannot maintain the clock and schedule during minor power fluctuations.

Heads Up

• Never mix programming methods; if you start a schedule on the app, finish it on the app. Switching between the wall unit and the phone frequently triggers the sync errors described above.
• Be aware that "Adaptive Intelligent Recovery" (AIR) may make it look like your schedule is wrong. The thermostat will start heating/cooling earlier than your set time to reach the target temperature exactly at the scheduled time.
• Avoid placing the thermostat near drafty windows or heat vents, as extreme temperature swings can cause the internal processor to glitch and trigger a reboot.
• If you experience a total system outage, always reprogram the web portal first, then let the device sync, rather than programming the wall unit manually.