I have been using Windows 10 tech preview for a while now running from an external USB 3 drive on my Retina MacBook Pro. It was running fine with no problems whatsoever. However, there must have been some recent update somewhere that screwed up my WiFi, so now when booting Windows 10 I no longer have access to the internet for more than a minute or so. This means Windows update obviously can't work. I just want to upgrade to the Windows 10 retail version before the tech preview expires (which is tomorrow). I don't want to clean install because doing that on an external drive requires a PC. I don't have an internet connection in Windows. Can I download something while in OS X that I can transfer to Windows and then do the whole upgrade there without a connection? Is there such a file or installer that performs a full upgrade and can be downloaded from a Mac? There must be a way to do this! Thank you! PS: To be clear, I don't mean some illegal way - I mean does Microsoft actually provide an "offline installer" that once downloaded, gets to work and upgrades the Win 10 tech preview PC on which it is being run, without needing an internet connection again? All I've seen so far are tools that download it for you - but those can't run on a Mac. Edit: Turns out that since my installation is on an external disk (which is officially supported in Windows 10), I cannot use the bootable USB stick ISO method to update it. I also can't update it via software update because it either doesn't work or I have no internet connection. I also can't fix the internet connection because the new BootCamp drivers are not signed and Windows refuses to boot from then on. I can disable driver signing but Windows update still fails to run. I ended up installing Windows 10 on an old PC, then using that to format and deploy the whole thing and just installing Windows 10 on the external disk from scratch, it was not easy (the PC has no backspace key, the battery is dead, the charger is faulty, has USB 2.0 and only has 1 GB of RAM so it was no fun) but still a lot easier than this crap! Except now I've lost my eligibility to get it for free as that only works when updating, not when reinstalling. How fun installing Windows always seems to be huh.