It might block network ports that Windows Migration Assistant needs to work. If Migration Assistant still doesn’t show your PC, try to turn off any Firewall software on your PC. You can create an isolated network if you connect a single Ethernet cable between your Mac and PC.

Use these steps to make sure that no other apps are open while you migrate:

If the steps above don’t work as you expect, try these options.Quit other Windows apps If so, use the sections below to troubleshoot further: I'd recommend verifying that you've followed all steps to move data from your PC to your Mac: Move your data from a Windows PC to your Mac I know how important it is to transfer your data to a new device and I'd like to help. I understand that you're seeing an error when you're trying to transfer files from your Windows 10 PC to your iMac running macOS High Sierra using Migration Assistant. Thanks for reaching out in Apple Support Communities.