Symptoms

After upgrade, the "Create" button no longer visible.

Diagnosis

Go to your Installation directory and Confluence Home Directory, and run below's command to show the folder's permission.

ls -al 

Cause

The user account running Confluence does not have the permission to write to the home folder.

Resolution

Make sure that your user have the permission to write on those folder or you can run below's command to gain access to all user.

chmod a+x 

The button will be triggered after pressing the shortcut key "C"