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copied!<p>UPDATE: see my comment for the best way to fix this. That said, to understand what's happening, this question is still informative...(end update)</p> <p>Solved (at least in my case). Here is what was happening:</p> <p>My view controller is used for displaying search results, and it stores those search results as an array of model objects. I use a custom UITableViewCell subclass to display each search result and, as part of configuring it, I store the associated model object (search result) within a property of the custom cell, call it <strong>myCell.modelObject</strong>.</p> <p>As I noted, the error was happening on every search <em>except the initial one</em>. To debug, I set a symbolic breakpoint on <strong>NSKVODeallocateBreak</strong> and saw that this was happening upon <em>re-using one of my custom cells</em>: </p> <pre><code>- (void)configureWithModelObject:(ModelObject*)aModelObject { // @property (nonatomic, retain) ModelObject *modelObject; self.modelObject = aModelObject; // <-- NSKVODeallocateBreak paused here .... } </code></pre> <p>So, my view controller, upon getting a second search result set, would release the array containing the original search's model objects. Those still retained by my re-usable custom cell instances would stick around, at least until those cells were re-used again. At that point, when self.modelObject is updated, the previous modelObject is released again and finally deallocates <strong>but because the cell that was observing it was not deallocated, but instead was re-used, my [modelObject removeObserver...] call in [myCell dealloc] was not called.</strong></p> <p><strong>Solution:</strong> When configuring my custom cell, I need to check if the model object is already set, which is an indication that this cell is being re-used. If so, I stop observing the original modelObject before updating the property:</p> <pre><code>- (void)configureWithModelObject:(ModelObject*)aModelObject { if(modelObject != nil) { // I'm being re-used! Stop observing old model object! [modelObject removeObserver:self forKeyPath:@"keyPathIWasObserving"]; } self.modelObject = aModelObject; // <-- NSKVODeallocateBreak paused here .... </code></pre> <p><strong>Note</strong>: I still need to call [modelObject removeObserver...] in [cell dealloc] to handle the situation where the view controller itself deallocates.</p> <p>I hope this is helpful to others with a similar pattern.</p> <p>Best, Steve</p>

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