The following post provides step by instructions for un-installing SQL server and related services.
It’s a good idea to back up all databases, including system DBs before performing the uninstall.
Navigate to control panel > Programs > Uninstall a program
2: Navigate to the program of SQL server with no size or version value. The instance needing to be removed from this machine is a 2016 version (64-bit). Double click the program.
3: A small window appears with three options. Click Remove.
4: We now have uninstall wizard. Select the appropriate instance from the drop down menu and hit next. In this case we will be uninstalling the default instance, thus MSSQLSERVER is the correct option in the drop down.
5: Select the features to uninstall. We will go ahead and uninstall all features.
6: After a rule check, we get a summary and configuration file path. The configuration file contains the commands executed during the uninstall. It comes in handy when trying to remember what steps were taken. When we need to uninstall multiple instances the config file can be used to automate the process.
7: After the features are removed we get the reward of green check marks and a summary log file path.
Note: Starting with SQL server 2016, the management studio application is disjoint from the server installation, thus it’s uninstalled separately as well.