I previously had windows 7 in my Bootcamp partition and upgraded to windows 10. Now the MacBook is very selective about which wireless routers it will connect with. It won't connect to a hotspot on my iPhone though it will with Mojave. It will connect with my wireless router but I don't have access to that now.

I have tried to download the windows support software pack onto a USB memory using the Bootcamp Assistant. All appears to go well until the end of the download when I get an error message 'Windows Support Software Cannot Be Saved To The Drive Selected'.

I've reformatted the drive in fat 32, exfat and fat with no difference. The drive is USB 3 but appears to work ok for saving and reading in both OS's.

I'd be grateful for any advice.

Thanks in advance,