Roundcube on cPanel failing with DB Error [14] unable to open database file

Roundcube on cPanel failing with DB Error: [14] unable to open database file — Root-Cause Fix

When Roundcube fails on INSERT INTO session, this is typically a write-path problem, not an application bug.

Key diagnosis points

• Per-account SQLite path:
• /home/USER/etc/domain.com/email@domain.com.rcube.db
• Validate ownership/permissions:

chown -R USER:mail /home/USER/etc
chmod 750 /home/USER/etc
chmod 640 /home/USER/etc/domain.com/*.db

• If corruption is suspected:

mv /home/USER/etc/domain.com/email@domain.com.rcube.db \
   /home/USER/etc/domain.com/email@domain.com.rcube.db.bak

Roundcube rebuilds the account database on next login.

Infrastructure layers that commonly break writes

1. CloudLinux/CageFS

cagefsctl --remount USER
cagefsctl --force-update

1. /tmp sanity and inode availability

ls -ld /tmp
df -h /tmp
df -i /tmp

1. Filesystem read-only remount

mount | grep -E ' / | /home | /tmp '

1. SELinux context mismatch

getenforce
restorecon -Rv /home/USER/etc

Last-resort package repair

/scripts/check_cpanel_rpms --fix
dnf reinstall cpanel-roundcube

Conclusion

DB Error [14] in Roundcube is usually an infrastructure write denial signal. A layered runbook (account -> temp -> filesystem -> confinement -> package) delivers fast, repeatable recovery.

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