Cannot Add Web Parts

In SharePoint 2010 situations arise when the ability to add web parts to web part pages using the UI becomes impossible.

In some situations, there will be JavaScript or other web parts that are executing incorrectly and throwing errors. Once the errors are resolved then it should become possible to add the web parts.

In other situations the cause is much harder to diagnose.

In the latter sitauation a workaround is to add “toolpanelview=2” to the querystring, prefixing it with ? or & as appropriate.