we are also facing same issue!
we have install latest version of Jenkins(1.643) and Java8 on windows 7 Enterprise, slave connected successfully using Java web start but file context menu is missing

If you check your logs, there should be errors looking a lot like this:

1) Error injecting constructor, java.io.IOException: javax.crypto.BadPaddingException: Given final block not properly padded
at org.jenkinsci.main.modules.instance_identity.InstanceIdentity.<init>(InstanceIdentity.java:38)
while locating org.jenkinsci.main.modules.instance_identity.InstanceIdentity
for field at org.jenkinsci.modules.upstart_slave_installer.SlaveInstallerFactoryImpl.id(SlaveInstallerFactoryImpl.java:23)

If that's the case, delete the files $JENKINS_HOME/identity.key.enc and $JENKINS_HOME/secrets/org.jenkinsci.main.modules.instance_identity.InstanceIdentity.KEY (and by "delete" I mean "move to a backup directory") and restart Jenkins.

Please report whether that was the problem, and whether the proposed solution worked.

No response to comment asking for additional information, so resolving as incomplete.

Please do not reopen, read my previous comment and only file a new issue if the described issue/workaround do not apply/work.

Hi,

we're having the same issues here. Jenkins is on 2.8 and we're trying to add a Windows 10 slave. The file menu briefly appears but then disappear. The work-around proposed does not apply: there's no such error in the event log (on the slave nor on the server), and the files we're supposed to delete does not exist.

Regards,

Nicolas Lacombe

Just create a scheduled task to start the agent on startup. We have been doing it this way since my last post and have had non issues.

While having a workaround is good, this issue should be resolved so that the intended behavior works.

Actually, the files proposed for deletion do exist, sorry about that.... but anyway deleting them does not solve the isse. Yes, using windows scheduler seems like a decent work-around, but nevertheless the issue should be logged somewhere, or fixed...

The reason I asked for a new issue was that we hopefully get something actionable, a 1.5 year old issue with 40+ comments just isn't. There may be multiple issues here.

Unsubscribing.

Same issue: i will open a new issue if that helps.

I have the same issue with the latest version of Jenkins, this took a while to figure out for me, but I found a work around. 

you'll need the Jenkins Slave Configuration XML and the Agent.jar file from your Jenkins webserver, as well as the secret keys. 

1. Logon to the server with the configured slave, and navigate to the Slave Directory.
2. Back this directory up
3. Copy the Agent.jar to the root of this directory. 
   1. this can be found by clicking the offline slave and looking at it's configuration, then you can just right click and download. 
4. Edit the Jenkins-Slave.xml
   1. Edit the below line, note that %BASE%\Slave.jar should be changed to agent.jar, and the URL should match what the Jenkins Master node is looking for if you don't know this value click on the offline slave it'll display it. ( Jenkins is case sensitive ). make sure the secret key matches the master.  
   2. <arguments>-Xrs -jar "%BASE%\agent.jar" -jnlpUrl http://Jenkins:port/computer/Computername/slave-agent.jnlp -secret XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX</arguments>
5. Save Jenkins-Slave.xml
6. Start the Jenkins service, it will take a couple mins to check in but should work.

Please let me know if this helps.