Windows 10 launched recently supports all features that Windows 7 and Windows 8.1 do. But this is not the case with MySQL. If you have a lower version of Windows installed on your machine with MySQL installed and it's been upgraded to Windows 10 then you're surely going to face a problem while launching your MySQL Workbench.
To have the dll, click here.
http://bugs.mysql.com/bug.php?id=75673
Here is the error you will receive,
There is a dll present in the Workbench installation folder named "HtmlRenderer.dll" which is required to launch the Workbench. After upgrading my machine to Windows 10, I've faced this error and did an extensive internet surfing for the solution. Finally, in a forum I got the solution saying this dll needs to be updated. A person has suggested to compile a source code from codeplex and asked to copy the dll in the Workbench installation folder. Another more kind person have compiled it and shared the dll over there. To make it handy to most of the people who cannot search for the forum, I'm providing that file for download in my blog.
To have the dll, click here.
After downloading, copy and replace the existing "HtmlRenderer.dll" with the new one and then your Workbench should be fine.
For more information regarding this error, here is the MySQL Forum's link which had discussed about it,
http://bugs.mysql.com/bug.php?id=75673