tmux session stops updating screen randomly

Question

I use tmux 1.6-2 on a Debian 7.6 (wheezy).

I open a new session and start a long running script that gives updates in form of a progress bar and an activity indicator (spinning bar: /-\|/ ).

When I detach and reattach everything is still fine. But after some random time when I reattach the screen content is stuck. No spinning bar, no progress. I looked into the following:

• I can see in top that the process is still running
• I can successfully enter tmux commands (like new window, detach, etc.)
• I can kill the script with Ctrl-C, but the tmux screen doesn't change
• Ctrl-S and Ctrl-Q (like suggested in other threads) doesn't help

Any help is very much appreciated.

Answer 1

I managed to unfreeze my tmux session by running choose-client command from tmux's command line <prefix> :

where prefix is C-b by default

I found the solution in the bug report (by Taisuke Yamada).