Steve wrote: > if I put an NSLog statement up in the 'for' loop and that causes a crash. ‘crash' or ‘appear to hang’ ? Here, sending the dictionary to NSLog on each iteration of the ‘for’ loop takes 22 minutes 34 seconds for 150,000 items. During that processing time, the NSLog window displays a snapshot of the screen area behind it. The same code in Xcode takes only 13 seconds to print (nicely threaded) to its console. Not sure how (or if it’s worth trying) to get around that in NSLog.incl. On a side note, I notice Xcode’s console is limited to around 32K of data for each NSLog call. So,in Steve’s demo, doing a NSLog(@"%@",mymutarr); before the array is emptied, truncates the data in Xcode console.