I can't create any folder through SharePoint interface(ribbon) in Document Libraries, and this happens only in document libraries and not lists across all of the Farm.
I have checked all things that came to my mind like:
- My user is System Account and have full access.
- My browser ran as administrator.
- "Make "New Folder" command available" is YES.
- "Allow management of content types" is YES.
- Tried accessing through different client machines, but no chance.
- In View settings "Show items inside folders" is selected.
- Created new Folder content type from the main one and added to Library but no chance.
- I'm able to create New Folder through Powershell, c# and Windows Explorer.
- Client Integration is enabled for web application.
- UAC is turned off, but still no luck. :(
I think this issue somehow related to the Farm and it's not a sitecollection problem or anything like that, because this problem is exist in all of my libraries in the farm.
This also happened one more time to me last year and i had to reinstall the SharePoint on another computer. I don't wanna do this again.
If happen to know any other way please tell me so i can test it.
With @AmitKotha suggestions i noticed something else, when i added some new and existed content types to the "Documents" library, not only the New Folder button was disabled, the New Document button was also disabled.
In fact all of my ribbon button on Files tab was disabled except the Upload Document button.
I think it's ok that all of buttons is disabled since no item is selected but not the New Folder and New Document buttons.