Calamari may hang on Windows when process crashes or is killed

[xwipeoutx]

Prerequisites

• I have searched open and closed issues to make sure it isn't already requested
• My team has started working on this issue
• I have written a descriptive issue title

The enhancement

The Need

On Windows, Calamari keeps a machine-wide lock for a Semaphore. A Semaphore on windows does not relinquish control to the next waiter when the process is killed, which means the lock is held indefinitely.

Solution

Switch it so Windows uses a Mutex instead. Add extra logging so the hang is easier to diagnose.

Screenshots and Mockups

N/A

Links

Calamari PR

[octoreleasebot]

Release Note: Fixed issue in Calamari on Windows where a crashed or closed process might result in locks not being released.

[team-builds-bot]

🎉 The fix for this issue has been released in:

Release stream	Release
2026.4	2026.4.2894