Cannot preview in Xcode

My computer setup is I work from an account with regular (non-admin) privileges. I login into the admin account to install apps, update the OS, that kind of stuff, but work is from the reduced privileges account.

And, when in it, I cannot preview swiftUI views in Xcode. Incredibly frustrating, have tried everything including a complete wipeout of the disk and reinstall, but no luck.

Don't have any iOS simulator targets installed, it's macOS target I am working on. If I fire up xcode from the admin account it's all good, previes work and so on. Not so in the non-admin account, consistenly getting the "Cannot preview in this file. Failed to launch xxxx"

Also tried elevating the privileges of the account to Admin, rebooting, no luck. Tried creating a new account, non-admin or admin, no luck.

The detailed error repeats something along the lines of:

== PREVIEW UPDATE ERROR:
    GroupRecordingError
    Error encountered during update group #3
    ==================================
    |  FailedToLaunchAppError: Failed to launch GIIK.Mesh-One
    |  
    |  /Volumes/Glyph 2TB/Developer/M4Book/Mesh One/DerivedData/Mesh One/Build/Products/Debug/Mesh One.app
    |  
    |  ==================================
    |  
    |  |  [Remote] JITError
    |  |  
    |  |  ==================================
    |  |  
    |  |  |  [Remote] XOJITError
    |  |  |  
    |  |  |  XOJITError: Could not create code file directory  for session: Permission denied

Most telling is the double space between directory and for on the last error line, it sounds like a failed string interpolation because the directory name was nil or empty?

This is very frustrating (I also filed FB21900410). Am I missing something obvious? I also dumped the build settings and diffed the admin and non-admin accounts and they are an exact match (save for the path names).

There has to be something that's preventing the non-admin accounts from previewing, anyone know what it might be/where to look?

Cheers,