The GNU screen is unresponsive, seems blocked
In the commands below, replace Ctrl with whatever your escape key is for screen commands.
Try Ctrl+a q, which is the sequence to unblock scrolling.
Ctrl+a s is the sequence that blocks scrolling, which makes screen seem like it freezes.
When using PuTTY, you can get an apparently freezed screen if you press Ctrl+s. This sends an Xoff signal blocking the terminal's output.
The solution is to press Ctrl+q to send the Xon signal.
The above works great if that is your issue.
This could also happen if you're ssh'd into another machine and haven't been to the window in awhile, then when you go back it's frozen. To fix this, you can try the following:
1) Create a new window
Ctrl-a c2) ssh into the box where you ssh'd into the box in the window that's frozen.
3) Find the process the ssh is running under:
ps aux | grep <remote_box_on_frozen_screen>or
ps aux | grep <your_user_id>4) Kill the process
kill <process_id>