Install Failure Error 2503

Fix: give everyone full access to C:\Windows\Temp, then retry the install.

Unverified whether this has side effects — flagged as a “pray it doesn’t” fix at time of writing, not confirmed safe long-term.

Followup

Error 2503/2502 during MSI installs is a classic “installer can’t write to %TEMP%” symptom — usually caused by restrictive ACLs on C:\Windows\Temp (often from a previous failed install, a security tool, or a permissions change). Granting Everyone full access is the blunt fix; the narrower fix is usually to reset inheritance on that folder specifically rather than leaving it wide open — see NTFS Permissions - Fixing Children for the icacls /reset approach, which would be worth trying first next time instead of a permanent full-access grant.