Recently I installed SharePoint 2013 Foundation to only realise I needed some of the features in SharePoint Server 2013. I upgraded the server and started running into strange errors as below:

1. Creating folders
2. Removing folders
3. Finding people in SharePoint

These issues above caused endless headaches, I tried the following as per MS:

1. Restart the SharePoint Search Host Controller Service
2. Added more memory to the server

Finally the solution was to enable Anonymous Access on the IIS site and then do an IIS reset. After doing that all those issues went away, I am sure this is a BUG in SharePoint 2013.

Hope it helps