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Updated on December 23, 2025 in #linux

Fix Open Terminal Failed Error with tmux

fix-open-terminal-failed-error-with-tmux.jpg

It's often caused by version incompatiblities from version upgrades.

Quick Jump:

I encountered this the other day when trying to attach to an existing tmux session with tmux a after I ran an update on a work laptop.

The exact error was: open terminal failed: not a terminal with tmux

It was either going from version 3.6 to 3.6a or 3.5 to 3.6a. In any case, it’s something to watch out for when you upgrade tmux versions. Sometimes there’s incompatibilities between the old tmux server and your upgraded tmux client.

Thankfully the fix is easy, just tmux kill-server and launch tmux. You can still use tmux resurrect to resume your old sessions.

# Demo Video

Timestamps

  • 0:13 – What causes this?
  • 0:36 – Use tmux resurrect to pick up where you left off

Did you ever have this happen to you? Let me know below.

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