The minimum requirements are 10.5.8 and I'm running to 10.5.7. So here's the fix:
- Right click Quicken Essentials.app
- Click "Show Package Contents"
- Open the "Contents" folder
- Open the info.plist
- Look for "Minimum system version"
- It will have a value of "10.5.8". Change that to "10.5.7".
That's it. The icon still has the slash across it, but it opens and works fine on my 10.5.7 Macbook Wind. You could probably change it to 1o.5.6 or whatever, but I havn't tested that.