Every sysadmin and developer who's worked with unreliable networks knows this frustration: your SSH session drops, but your precious screen session refuses to reattach. The standard screen -D -RR command hangs indefinitely, leaving you staring at an unresponsive terminal.

The issue typically occurs when:

• The socket file in /var/run/screen/S-username/ gets corrupted
• Process permissions become misaligned after abrupt disconnects
• Network timeouts don't properly clean up the session

When standard reattachment fails, try this sequence:

# First attempt graceful detach
screen -D

# If that hangs, find all screen processes
ps aux | grep '▼显示creen' | awk '{print $2}' | xargs kill -9

# Clean up socket files
rm -f /var/run/screen/S-$(whoami)/*

# Then retry
screen -D -RR

If the standard approach fails, try specifying the exact session:

# List available sessions
screen -ls

# Reattach specific session forcefully
screen -r -d 12345.pts-1.server

Add these to your ~/.screenrc to minimize issues:

# Increase keepalive packets
deflogin on
autodetach on
altscreen on
# Reduce timeout to 30 seconds
escape ^Zz
msgwait 30

For persistent screen issues, consider tmux as a more resilient alternative:

# Basic tmux commands:
tmux new -s session_name
tmux attach -t session_name
# Detach with Ctrl-b d

For Putty users, these settings help prevent disconnections:

1. Connection → Seconds between keepalives: 30
2. Connection → Enable TCP keepalives
3. Terminal → Features → Disable anti-idle (OFF)

---

As a developer working with remote servers through PuTTY, I frequently encounter unstable wireless connections. GNU Screen has been my lifeline for maintaining persistent sessions, but sometimes reattaching becomes impossible. The classic screen -D -RR command just hangs indefinitely, leaving me stranded.

When this happens, several processes might be involved:

$ ps aux | grep screen
user   1234  0.0  0.1  12345  6789 ?        S    Jan01   0:00 SCREEN -d -m
user   1235  0.0  0.1  23456  7890 pts/1    S+   Jan01   0:00 screen -D -RR

The session exists but becomes unresponsive, often due to:

• Terminal state corruption
• Permission issues
• Broken pipe connections

Method 1: Forceful Detach and Reattach

Try this sequence:

$ screen -D # force detach
$ screen -r # attempt reattach
$ screen -list # verify session status

Method 2: Kill All Screen Processes

More aggressive approach:

$ pkill -9 screen
$ rm -f /run/screen/S-$USER/*
$ screen -wipe
$ screen -Rd

Method 3: Terminal Reset

Sometimes the terminal needs resetting:

$ reset
$ stty sane
$ screen -r

Add these to your .screenrc:

autodetach on
defescape ^Zz
zombie az

For PuTTY specifically, configure:

• Seconds between keepalives: 30
• Enable TCP keepalives
• Disable Nagle's algorithm

Consider these more modern alternatives:

$ tmux new -s mysession
# or
$ byobu

Both handle network interruptions more gracefully than GNU Screen.