Inkscape very slow to start up on Windows

Turns out the issue was with the Open Recent History. All of the SVG files I open are stored on network shares and move around quite a bit. Disabling this feature resolved the problem permanently. So, I suspect Inkscape verifies and/or reads various information about the files in the Open Recent History.

• File > Inkscape Preferences (SHIFT+CTRL+P)
• Interface
• Click on Clear list
• Set Maximum documents in Open Recent to 0

The approach in Drew Chapin's answer made quite a difference on my machine.

Also, startup is slower the more fonts you have installed, according to this forum discusson:

I deactivated all fonts that are almost never get used (approx. 2/3 of them). And now Inkscape starts a lot faster.

I wasn't aware I got so much fonts installed, because I did not install them myself. Probably they were automatically included in the install process of some graphic and text applications I use.