Since Logitech removed the original desktop software (which will no longer work for updating controllers), we were able to get a copy which can still at least be installed successfully and then, by launching a local firmware file (below), Windows will recognize that the software is installed and you may be able to successfully re-apply the firmware. This may not always work and should only be done as a last resort.
| Logitech Harmony Software 7.7.0-win-x86.exe |
| harmony_one_firmware_3_4.hfw |