If post-install is run as root /tmp/columnstore_tmp_files gets set as root owner with 775 permissions which means it is not writable by the non-root user.

It should either be owned by the non-root user or have permissions set to 777 (preferably the former). This could be solved by having the directory created at usage time rather than at install time (where tmpfs may erase it at reboot time anyway).

Reproduction steps are likely:

1. Install a multi-node setup as non-root
2. As part of the install run post-install as root
3. Run getmodulecpuusers from mcsadmin