On an Ubuntu 12.04.4 LTS box, we updated a config which then propegated changes from a bunch of plugins via Jenkins->Manage Jenkins->Configure System and when added some info for an Artifactory server. This caused unknown behavior that was causing all attempts to edit Job configs to cyclically request credentials, never-ending.

To recover, we removed newly propegated XML files from /var/lib/jenkins and made backups of what was left, then viewed the old `good` configs with the jobHistory plugin, saved those as XML files, and then copied them into /var/lib/jenkins

This reversed the issue of no longer being able to edit configs, but injected a new issue. We cannot successfully install any new plugins with the Web-GUI, nor can we `Check Now`

Proxy info not set in Web-GUI but on the ubuntu box itself. No proxy info should have been updated as we were just addressing plugins.

Attachment shows example error for "java.io.IOException: Downloaded file /var/lib/jenkins/plugins/plugin_name.jpi.tmp does not match expected SHA-1, expected 'SomeSHA=', actual 'SomeOtherSha='"

When trying Check Now with http://updates.jenkins-ci.org/update-center.json, getting this error also completely shown in other attachment: "javax.servlet.ServletException: java.lang.IllegalArgumentException: Could not find (numeric) updateCenterVersion in..."

We then tried updating Jenkins from 2.x to 2.7 – this did not change the behavior, which surprised us to be frank.

How can we fix the update center queries, even if it is a workaround? Right now all plugins have to be handled manually...