Heads up: SQL Server 2014 SP1 On Hold
If you started the process of testing and getting read to install SP1, you’ll want to hold off. There are some issues with it that Microsoft will be addressing in a re-release of the service pack as soon as they’re ready.
In the meantime, hold off on the installation and/or testing.
Here’s the official word:
We have chosen to remove SQL Server 2014 Service Pack 1 (SP1) from the Microsoft Download Center due to a significant installation issue discovered shortly after release. We sincerely apologize for the inconvenience this has caused you.
We will fix the installation issue and release the Service Pack for production use in a few weeks. Although operationally equivalent, only the newly released SP1 will be serviced (security updates, cumulative updates, hotfixes). Therefore, it will be important that you replace the current version of SP1 (12.0.4050.0) with the upcoming one.
You can get more information here at the MSDN site, including information about the issue found, and workarounds.