Yeah, Quicken 2010 is ancient now, but it works just fine for our purposes!
However, when upgrading from a beta version of CrossOver 17.0 on my Mac, Quicken 2010 stopped working. The app would load, but no window would appear. Thankfully, I stumbled upon a fix.
In the Quicken bottle, I selected the Gear Icon > Settings > Use Legacy X Window System. I then restarted Quicken 2010 and it worked fine; I then deselected the "Use Legacy X Window System", restarted Quicken 2010 and everything seems back to normal.
Not sure why that worked, but just in case anyone else runs into problems, I hope this helps.