Update: Version 1.67 which may fix this issue was made available at about 5am UTC on 18th June. Please update if you haven't already.
Update2: No crashes in version 1.67 up to this point (about 32 hours since release). Looking good so far.
When the 1.66 version was initially posted I received a sudden flurry (15 apparently from four or five different users) of crash reports within the first 12 hours of release coming from the deletion confirmation that I put in place.
I tested again on my device and could not reproduce the problem. Reviewing the code again I spotted what seemed to be a potential cause that may have caused issues if the problem occurred on the deletion of the first (topmost) list. This one character fix (changing greater than to greater than or equal) was submitted that first evening to Apple for review as version 1.67. The status changed to "In Review" at a little after 7pm yesterday (Tuesday) so I expect it should be available soon and I hope that it will resolve all these crashes.
Until I started writing this blog post there had been no further crash reports since 6 am yesterday (40 hours ago) although since starting this post another four crash reports have arrived apparently all from one user.
If you have suffered a crash in Fast Lists please email me and let me know what was happening at the time and any details that you can remember. Email me about this or any other issue at firstname.lastname@example.org
This case more particularly than others I am interested in information as I haven't been able to reproduce the problem on my own test devices which is very valuable to confirm the details of the problem (especially if I can observe it in the debugger) and to confirm that the fix made really fixes the issue.
To all those who have suffered crashes I send my apologies. It isn't acceptable performance from my software I expect it to be almost entirely crash free.
Other Known Issues
On occasions there is an issue loading data from the Core Data system that Apple provides on their computing devices. When this happens (especially when trying to update the list) Fast Lists crashes rather than continue operating in way that may lead to your changes not being properly saved. When next started Fast Lists will try to verify all the data and ensure a consistent state.I suspect that this is when an item is being edited and it is deleted underneath it. I think it only happens on the iPad and I think I have identified the most significant location where this happens and I am preparing a 1.68 version to submit when 1.67 is released by Apple. Apologies for all these updates.