Since version 1.14. winsw uses sigint for terminating processes. This seems to be incompatible with Jenkins.
The Jenkins plugin Safe Restart is no longer able to restart Jenkins

jenkins.wrapper.log

2014-06-12 10:34:22 - Stopping jenkinsmaster
2014-06-12 10:34:22 - ProcessKill 2208
2014-06-12 10:34:22 - Send SIGINT 2208
2014-06-12 10:34:22 - SIGINT to2208 successful
2014-06-12 10:34:22 - Send SIGINT 2208
2014-06-12 10:34:22 - SIGINT to 2208 failed - Killing as fallback
2014-06-12 10:34:22 - Finished jenkinsmaster

jenkins.err.log

Jun 12, 2014 10:34:11 AM jenkins.model.Jenkins$24 run
INFO: Restart in 10 seconds
Jun 12, 2014 10:34:21 AM jenkins.model.Jenkins$24 run
SEVERE: Restarting VM as requested by bberbuir
Jun 12, 2014 10:34:22 AM jenkins.model.Jenkins$24 run
WARNING: Failed to restart Jenkins
java.io.IOException: Restarting a service
[Jenkins] $ "C:\Program Files\Jenkins\jenkins.exe" restart

at hudson.lifecycle.WindowsServiceLifecycle.restart(WindowsServiceLifecycle.java:132)
at jenkins.model.Jenkins$24.run(Jenkins.java:3323)