Here's some clarity for anyone looking. The root cause of the sign in when switching the host is that programs often store their license information x'ord (or otherwise encrypted with) a hash of the host hardware. This means that, when the hardware changes, the previously stored configuration is unrecoverable. I've tried spoofing the MAC address, but all programs I test seem to do a deeper hash using the hardware (e.g.
system_profiler). I've found a number of workarounds, though:
- Stop using apps from the App Store. While the app store uses this hardware hash technique, many indie programs don't. For those, buying directly works (e.g. Moom)
- Where possible store the license information in an un-hashed version. For example, Sublime Text supports this by editing the license file (see https://forum.sublimetext.com/t/st3-license-not-syncing/11738)
- I've found that the iCloud sign in behavior stopped when I created my own keychain (not the default
login) and set it as default. Not using an App Store apps, and using this new default keychain, I get no prompts to log into my iCloud account on start up
After this, some programs that are still offensive are: Office 365, Creative Cloud, and Mathematica. I ended up finally ditching Creative Cloud - I've long switched to other tools, so the one part that I still use (Font syncing), I just downloaded all the fonts locally.
Overall this is pretty good now. After switching hosts, I get zero dialogs to log in. All my main flows work (Thunderbird, terminal, Sublime). Occasionally I have to log in, but much less of an issue than before.
Hope this helps.