Steps to reproduce:

1. Install zabbix agent 2 (tested on 5.2.7 and 5.4.3) on target Windows 10 or Windows server 2019 host.
2. Install smartmontools latest version.
3. Add host to zabbix with template smart by zabbix agent 2 (or smart by zabbix agent 2 active).
4. Wait for item update.

Result:
Items related to smart monitoring show error:
> Failed to scan for devices: Cannot unmarshal JSON: invalid character '\u00ad' after top-level value..
 
Manually added test item "system.run[C:\zabbix\smartmontools\bin\smartctl.exe --scan-open]" returns correct result:
> /dev/sda -d nvme # /dev/sda, NVMe device
 
Manually running smartctl.exe from command line also return correct results.
 
So it is not a permission problem. Tests show that there is no difference if smartmontools installed to default path (C:\Program Files\smartmontools) or to any other directory.
 
Side problem: smartmontools not adding itself into PATH (despite it has default-on option in installer). After adding smartctl to PATH manually, error changes to:

• Smartctl failed to get device data: unknown error from smartctl.

Expected:
Working smart monitoring.