Blank terminal
What “Blank terminal” usually means
When PuTTY reports Blank terminal, the client has already attempted a network or protocol step and failed before a normal interactive shell is available. This guide explains what the message usually means on Windows clients, which local settings to verify first, and when the problem is almost certainly on the server, firewall, or DNS path rather than inside the PuTTY GUI.
A session appears to connect but the terminal stays blank—shell not started, wrong remote command, color-on-black issues, or waiting on input not shown.
Independent resource: Putty.info is educational only and is not affiliated with the official PuTTY project. Compare symptoms against the official documentation for your installed version.
Symptoms you will see
Operators usually notice this failure in one of a few repeatable ways. Capture the exact dialog text, the hostname and port from the Session panel, and whether the failure happens before or after a username prompt—those details decide which checklist below applies.
- Black or empty window after “connected”.
- Sometimes fixed by resizing or pressing keys.
Likely causes ranked by frequency
Several independent conditions can produce the same client-facing wording. Work from the outside in: reachability first, protocol selection second, authentication third. Changing key files will not fix a TCP refusal, and opening a wider firewall will not fix a rejected public key.
- Remote command configured to run a GUI or exited immediately.
- TERM or locale issues producing invisible output (rarer).
- Foreground/background color both dark.
- Still negotiating auth while UI looks idle.
Step-by-step client checks
Use this ordered checklist on a workstation you control. Prefer saved sessions so Host Name, Port, and Connection type stay consistent while you isolate one variable at a time.
- Clear Connection → SSH → remote command for testing plain login.
- Reset colours under Window → Colours to defaults.
- Confirm auth completed (Pageant passphrase prompts can be easy to miss).
- Try another account with a simple bash/sh shell.
- Enable Session → Logging temporarily to see whether bytes arrive.
- Update display drivers only if the entire Windows UI glitches—usually not PuTTY-specific.
Do not paste private keys, passphrases, or production passwords into Putty.info tools or contact forms. Diagnose locally with PuTTY, Plink, PSCP, or PSFTP from an official install.
When it is a server or network issue
Ensure the account shell exists and motd/pam messages are not wedged on a missing device. ForceCommand should be intentional.
If TCP connects from another network path but fails from yours, involve the network team with traceroute/path evidence rather than repeatedly regenerating keys. If authentication fails after a banner appears, collect the server sshd logs for the same timestamp and username—client-side retries alone rarely reveal AccountLocked, Match blocks, or AllowUsers denials.