This crashes as a result of line 3. Is this not how you perform searches using MagicalRecord.

gistfile1.txt

[MagicalRecord saveWithBlock:^(NSManagedObjectContext *localContext) {
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"match == nil && failedChoice == NO"];
    NSArray *users = [TNDRUser MR_findAllWithPredicate:predicate inContext:localContext];
    for (TNDRUser *user in users) {
        [user MR_deleteEntity];
    }
} completion:nil];