The knowledge base does not have a direct answer for how to “clear” a false fan error.
What it does show is this:
- If an ALERT LED is blinking red or DSM says the fan has stopped working, the documented fix is to verify the fan is correctly installed and functional, and replace the malfunctioning fan if needed. This is described in the manuals for DX1215, DX1215II, SA3200D, RX1213sas, DS1621xs+, and related models. [1][2][3][4][5]
- For systems that use DSM 6.2.3 and earlier, the SA3200D manual explicitly notes that later DSM versions may use different instructions. [4]
- One community post mentions a workaround that disables fan checking via SSH and a scheduled task, but that is a forum workaround, not an official KB fix, and I should not present it as a recommended solution. [13]
So, based on the provided fragments, the supported action is:
1. Verify the fan is properly installed and its connector is seated correctly.
2. Replace the fan module or fan if the warning persists.
3. For models covered by the manuals, follow the exact replacement procedure for that model.
If you want, I can help you identify which of the listed manuals is the closest match to your Synology model and summarize the replacement steps from that source.
Sources used: [1], [2], [3], [4], [5], [13]