What you’re running into is a classic case of user rights assignments on a domain controller being way more sensitive than Splunk’s docs make it sound. The “Bypass traverse checking” setting is indeed the usual culprit when logon screens go black, because if you strip out groups like Everyone or Authenticated Users, you basically cut off the OS from being able to enumerate paths for normal logons. Adding SYSTEM back in doesn’t fully fix it if those defaults are missing.
The secedit command error you’re seeing is usually about syntax or the database path . Double‑check that your /db argument points to a valid .sdb file and that you’re not accidentally overwriting a locked database. Also, when you export and re‑import, you need to make sure the policy refresh actually applies; sometimes PDQ pushes don’t trigger a full user rights refresh until after a reboot.
think the safest way forward is to roll back the GPO changes for “Bypass traverse checking” to defaults (restore Everyone, Authenticated Users, etc.), then reapply Splunk’s required rights only to the Splunk service account, not SYSTEM or SERVICE globally. Running Splunk directly on a DC is always dicey, but since you inherited this setup, the rollback plus a clean redeploy of Splunk’s rights should get you back to a working login state.