Is there an easy way to import all the extensions and preference from the 2016 version to the new one?
The easiest way to get most of your extensions into a new version is to use the facilities provided by the Extension Warehouse and the sketchUcation plugin store, both of which can remember a collection and reinstall it. It is always better to reinstall than simply copy, since each release of SketchUp can introduce incompatibilities that the extension authors then fix in their next update.
Most other preferences are usually automatically brought into the new version of SU. Are there some specific ones you have lost?
Preferences (MS Windows)
Window > Preferences > Shortcuts > Export…
Save the file somewhere where you can import it in SU2017, from the same dialog, but using the Import… button.
For Mac info, see later post by Steve.
(Steve answered Extensions part.)
I saw the export and import but you can get only one at the time it’s probably faster to start from scratch also because maybe there are incompatibility as slbaumgartner pointed out
Note that @DanRathbun’s answer applies only on Windows. There are no keyboard shortcut export or import buttons on Mac. This is because on Windows the settings are kept in the Registry, whereas on Mac they are kept in the Shortcuts.plist file. Editing the Windows Registry yourself is risky even if you think you know what you are doing. It’s too easy to render an application or even the whole system inoperable if you make a mistake. So the export/import capability is necessary for normal users who want to move their keyboard shortcuts from one install to another. In contrast, the Shortcuts.plist file on Mac is plain text, so there is no system risk involved with accessing or manipulating it.
I know that keyboard shortcuts are automatically imported to a new version of SketchUp on Mac. Does that not happen on WIndows?
I think it does, because I see that there is an “I” shortcut set for Entity Info that does not actually work for SketchUp 2016, so it must have been imported from 2015 or earlier, and another “X” that toggles X-ray render mode, that I know I set in 2016.
So they must get imported during installation.