SketchUp Make slow on Windows 10

[DanRathbun]

SketchUp 2015 was released in 2014. It cannot possibly support Windows 10, without some updates.

You might have referred to SketchUp Hardware and Software Requirements before you upgraded.

Also see this bulletin by the SketchUp Team:

Early Adopters (of New OS Versions) Be Cautious

Yesterday was the launch of Windows 10 with free upgrades for many existing Windows customers. While we aren’t finding anything that’s going to ruin your day, I wanted to post a reminder that new software and especially beta software (I’m looking at you El Capitan) are not known for their reliability. We strongly recommend having restore options to go back to the previous version of Windows if you’re going to jump out there and upgrade. If you do install Windows 10 and run into issues, be sure t…

You might try running SketchUp in Compatibility Mode for Windows 7 or 8.
Right click the SketchUp shortcut, and choose Properties, switch to the Compatibility tab, and select a mode to run in, then click Apply or OK. (No guarantees.)