The symptom
In step 2, this command printed nothing and never returned:
copydocker compose exec client-a bash
No prompt, no error. Ctrl + C didn’t free it. Only restarting the container did.
Narrowing it down
Each test was chosen to rule one thing in or out.
| Test | Result | What it told us |
|---|---|---|
Press Enter, type hostname | Nothing | Not just a hidden prompt; the session really was stuck |
docker compose exec client-a hostname (no interactive terminal) | Hung too | It wasn’t only interactive sessions. Docker’s exec itself was stuck |
wsl --shutdown, restart Docker Desktop, docker compose up -d, then the same hostname command | Worked | Docker was healthy again; the earlier stuck session had jammed it |
docker compose exec client-a bash again, same window | Hung | The interactive session was the trigger, every time |
Update Docker Desktop (4.95.0 to 4.96.3), then bash in the regular Command Prompt | Worked | Something about the window or the old version was the cause |
The cause
The commands were being run in PowerShell ISE. ISE looks like a terminal but isn’t one: it can’t hand the keyboard to an interactive program like bash, telnet or ssh, so the session waits forever. The same window had also been showing Docker’s normal progress messages as red NativeCommandError text, an early clue that was easy to dismiss.
The fix
Use Terminal (or the regular Windows PowerShell or Command Prompt), never ISE. If Docker is already stuck:
copywsl --shutdown
Then start Docker Desktop, wait for Engine running, and from the lab folder:
copydocker compose up -d
What to take from it
- Test the simplest thing first. A one-line command with no terminal (
hostname) separated “Docker is broken” from “interactive sessions are broken”. - One stuck session can jam everything after it. Reset before drawing conclusions from the next test.
- Change one thing at a time. Here, Docker was updated and the window changed back to back, so strictly either could be the fix. The check that settles it: run
bashonce more in ISE on the new version. (Not run yet, so treat the cause as very likely, not proven.) - Odd warnings are clues. The red text was the first sign the window was wrong.