Fresh on the heels of the news last week of Service Pack 1 being released for SQL Server 2016 comes a little word of warning. First the good news, SP1 has unlocked an awful lot of Enterprise functionality for the Standard, Web and even Express editions; more on that here.
All of that is very good however a word of warning has been issued from the MSSQL Tiger Team if you are using SP1 on the "lower" version: "you might see some unforeseen errors or databases might even be left in suspect state after uninstallation of SQL Server 2016 SP1. Even worse would be if the system databases are using new features for example, partitioned table in master database, it can lead to SQL Server instance unable to start after uninstalling SQL Server 2016 SP1".
If you have installed SP1 and now wish to uninstall it you need to ensure that any of the new features have been disabled and/or dropped from the system. The blog post comes with a handy script to verify if any of the functionality is enabled. You can read all about it (and some other warnings) here on the MSSQL Tiger Team blog, oh and the uninstall works fine in Enterprise Edition.