I am upgrading my confluence test instance from version 4.3.2 to version 5.5.7.
finally every thing was working fine after upgrade(After resolving some issues), except workbox tab which is not working.
So to resolve it i was trying the solution mentioned in below link.
https://confluence.atlassian.com/display/CONFKB/Unable+to+Enable+Workbox's+Notifications+and+Tasks+-+Host+Plugin+Due+to+NoClassDefFoundError
and started with disabling workbox-common plugin after disabling common plugin tried disabling host plugin it was not responding.
So i restarted the confluence server.
after restart workbox-common plugin is shown as enabled, so i disabled it again and tried to disable workbox-host plugin but it is listed under user installed plugins and only uninstall option is shown as below.
image2015-4-13 12:50:28.png
Please help me to resolve it
Thanks in advance.