As mentioned in
this KB article, Lansweeper only uses the IP as unique identifier if no MAC address was scanned. If possible we recommend that you try scanning your device through SNMP. This allows to scan the MAC address and get around this problem in case of IP address changes. You might need to activate SNMP on the device itself before scanning it. Details on how to scan network devices can be found in
this KB article.
Edit: It seems from your screenshot that in your case the same Windows computer was scanned both as Windows asset and as unknown network device. This happens if computers were scanned on WiFi or VPN connections and port 135/TCP was closed. In order to resolve this, either open port 135 on WiFi/VPN or reconfigure your scanning schedules under
Configuration\Scanning methods, section
IP Address range scanning, and let these scans only be performed during the night when no WiFi or VPN connections are in use. If you need to scan Windows computers but you can't open 135/TCP or Windows remote administration can't be enabled between your Lansweeper server and scanned machines, you need to scan them with
LsPush.