Quicken is one of the best-selling programs in the history of the Universe. Pretty much everyone that has owned a PC or Mac since the late 80's has had a copy of it lying around somewhere, and lots of people actually use it to keep track of their finances. Why? Because it works pretty well and Intuit has (to their credit) done a good job of keeping up with what people want the program to do.
They've done such a good job, in fact, that lots of Linux folks keep a Windows partition on their machine just so they can run Quicken and the latest shoot-em-up games. So of course we want to give you a way to suck all your Quicken data into GnuCash and remove one more barrier to putting a nice ext2 filesystem on that Windows partition.
The problem is that GnuCash is a real double-entry accounting system and Quicken has a pretty simplistic view about what an account is, what a transaction is, and, most critically, is severely flawed in its datamodel, that is, what it saves in data files.
Briefly, QIF files just don't contain enough information to completely and accurately reconstruct your Quicken account hierarchy in the GnuCash double entry system without some educated guessing by the import code as well as some guidance, provided by you.
QIF files omit small things that may be fairly accurately inferred by examining the data.
For instance, are numbers in decimal-radix [1,000.00 == 1000] form or European comma-radix form [1.000,00 == 1000]?
Or are dates
More problematic are major things where there is little way of guessing.
For instance, determining the currency the file is denominated in.
Or what account the file describes.
GnuCash's QIF importer does a remarkably good job of guessing what it can, but you do have to keep an eye on it. Fortunately, the system is designed so that you can correct problems before you changes are dropped into your GnuCash accounts. Nothing is done to your GnuCash accounts until you click the final "OK" button.
In the next section, I'll give an overview of the QIF file and its "features". This may seem unnecessarily technical, but if you at least glance through it you will be much better able to understand what's going on if you are having to jump through hoops to make make a problematic file work right, and how you might be able to jump right in and edit the QIF file to fix really tough problems.
There are two major "paths" for using the GnuCash QIF importer.
One is the "I am a Quicken user just migrating to GnuCash" path.
The other is the "I am downloading some updates from my bank as a QIF file" path.
This document mainly focuses on the former case, since new users are likely to need the most help and you really can't get started using GnuCash until you can get your old records in. Fortunately, once you learn to do the former, the latter should be a piece of cake.