Updated: 28 September 2026 · Applies to: Plesk Obsidian 18 on AlmaLinux and other RPM-based systems
CentOS 7 is end of life. On a Plesk server, errors such as Failed to initialize NSS library or rpmdb open failed mean that the package manager itself is broken, usually after an interrupted update. Plesk cannot work until it is fixed. These steps apply to AlmaLinux and other RPM-based systems.
1. Rebuild the RPM database
cp -a /var/lib/rpm /root/rpm-db-backup-$(date +%F) rpm --rebuilddb dnf clean all dnf check
2. Reinstall the NSS libraries
If rpm still fails with the NSS error, the nss and nspr packages were updated only partly. Reinstall them together:
dnf reinstall nss nss-util nss-softokn nss-softokn-freebl nspr
If dnf itself cannot start, download the matching packages for your exact OS version on another machine and install them with rpm -Uvh --replacepkgs, or ask our support team.
3. Repair Plesk
dnf upgrade plesk repair installation
Then log in to Plesk again. If the server still runs CentOS 7, plan a move to AlmaLinux 9 (see "Upgrading Plesk 12.5 to Onyx").
