Today VMware support raised a high alert to customers not to upgrade their vCenter oracle databases to patch 10 or later since it causes some issue with vCenter server specially when creating virtual machines. for example when creating a new virtual machine you get the following error.
An internal error occurred in the vSphere Client.
Details: Object reference not set to an instance of an object
VMware is currently reviewing the issue and there is no available workaround. if you have already upgraded, you will need to revert back to the old oracle binaries and database recovery may be required
More information on this is available in VMware KB Article 2039874
Keep reviewing the KB for updated information.