Email and Webmail

Cannot write to cache directory /tmp/horde

Updated September 2026 20,384 views 2 min read
Email and Webmail | Updated September 2026

The "Cannot write to cache directory /tmp/horde" message comes from the Horde webmail client. Horde is being retired from cPanel in favor of Roundcube, so the simplest fix is to switch to Roundcube, which is faster, actively maintained, and does not hit this error.

01. Why This Happens

Horde stores temporary cache files under your account's ~/tmp/horde directory. If the permissions on that folder are wrong - usually after a migration, a permissions reset, or a disk-quota event - Horde cannot write its cache and shows this error. Because Horde is on its way out, we recommend moving to Roundcube rather than repairing it.

Tip

Switching webmail clients does not move or delete any mail. Roundcube and Horde both read the same mailbox on the server - only the interface differs.

02. If You Still Need Horde Temporarily

While Horde is still available during the transition, you can clear the error by resetting the permissions on its cache directory:

  1. Log in to cPanel and open File Manager (enable "Show Hidden Files" in Settings).
  2. Find the tmp folder in your home directory, then the horde folder inside it.
  3. Set the tmp and horde folder permissions to 0755 (or 0700), then reload Horde.
  4. If your account is over its disk or inode quota, free up space first - a full account also blocks Horde from writing its cache.
Recommended

This is a stopgap. Horde is being removed from cPanel, so move to Roundcube when you can to avoid the issue returning.

03. Related

See the Email Troubleshooting Guide for general webmail and mail-client help, or set up email on your device with our Outlook, iPhone/iPad, and Android guides.

Still Stuck on Webmail?

If Roundcube will not load or you are missing mail after switching, open a ticket and we will check the mailbox and account permissions for you.

Open a Support Ticket
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