See: https://confluence.atlassian.com/pages/viewpage.action?pageId=394463234

The Macro Browser constantly fails to load in Confluence 5.2.3 with the following unhelpful error:

java.lang.IllegalStateException: Cannot retrieve plugin module before it is enabled: PluginModuleHolder[(unknown; not enabled)]

It's difficult for us to identify exactly which plugin is causing the issue, hence, the spike in support loads. This does not occur in 5.1.x even with incompatible plugins.