[NullReferenceException: Object reference not set to an instance of an object.]
   umbraco.controls.ContentControl.addControlNew(Property p, TabPage tp, String Caption) in d:\TeamCity\buildAgent\work\7380c184e9fcd3ea\umbraco\presentation\umbraco\controls\ContentControl.cs:210
   umbraco.controls.ContentControl..ctor(Content c, publishModes CanPublish, String Id) in d:\TeamCity\buildAgent\work\7380c184e9fcd3ea\umbraco\presentation\umbraco\controls\ContentControl.cs:81
   umbraco.cms.presentation.editMedia.OnInit(EventArgs e) in d:\TeamCity\buildAgent\work\7380c184e9fcd3ea\umbraco\presentation\umbraco\editMedia.aspx.cs:79
   System.Web.UI.Control.InitRecursive(Control namingContainer) +333
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +378

Yikes, that's a new one for me.

Does it happen with every folder? Do individual files upload ok? Can you upload files via the Media section ok?

Bit of a tricky one actualy, as none of the stack trace actually references any of my code.

Done a quick search, and a few people have had similar (but not the same) problem. I'd also try restarting your app pool.

Matt

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