If you're importing assets that will be scanned later, keep in mindhow Lansweeper uniquely identifies assets. If your import file does not include the information Lansweeper uses for its internal asset IDs, new assets will be generated upon scanning.
For Windows computers specifically, you need to submit the machines' actual computer names and domain names in your import file. Alternatively, enable rename detection and submit the machines' MAC addresses, models, and serial numbers. For non-Windows assets, you need to submit the assets' MAC addresses or IP addresses.