"Error while relocating" after deleting RAW from RAW+JPEG pairs (Important FYI)

Question

This is not a question, but something I recently discovered that I think will be important for the Aperture community.
Not too long ago, I asked a question about how to remove the RAW files from RAW+JPEG pairs. The concensus was that it couldn't be done through Aperture, but that one could delete them through the Finder. The answer I got (and that has popped up in other threads on similar topics) was "it's probably not wise, but as far as I know, it won't have an adverse effect." I don't think any response along these lines has been able to point to a specific problem that can arise from such a "hack." Well, I found one today...
It appears that if a user uses Finder to "break" RAW+JPEG pairs by deleting the RAW file and leaving the JPEG (and I assume this goes for deleting the reverse), Aperture will NOT be able to "Relocate Originals..." Instead, "Aperture will return the error: Error while relocating (File not Found): "(null)". I ran into this error the other day while trying to change my file structure by relocating all files. I regularly ran into this error, and it was only after some extensive that I was able to narrow it down 100% of the time to the RAW+JPEG pairs I had "broken." I haven't encounterd any other adverse behavior from "breaking" these file pairings, but this one, at least, could be serious.
So, for future reference, I think the response by the Aperture community when someone asks "How do I delete the RAW file from RAW+JPEG" pairs, should be "Use Finder if you must, but please note Aperture will not be able to 'Relocate Originals..
PS This should NOT be understood as a criticism of those who have responded to this question in the past. There's obviously no way to know about these little quirks until one of us stumbles across them. I hope this information will be helpful going forward, both as a caution when deleting one of the pair, and as a possible answer for the "Error while relocating" message.
PPS I don't think I ran across an explanation for this when I originally searched for the error message bolded above.
If someone has already provided this information, my apologies.

Answer 1

Frank Caggiano wrote:
Interesting the last post before this one you posted was back in May 2011 Removing RAW, keeping JPG?
Thanks for that thread. That helps jog ye olde memory. As such, I would edit my original thread to read "The concensus I gathered from researching multiple responses to questions similar to mine was that it couldn't be done through Aperture*, but that it was possible from Finder though highly inadvisable." I won't bother recreating my research at the time (not even sure I could, since it was more than two years ago), but suffice it to say that the thread you've linked was not my sole encounter with this problem. I do appreciate that you've reminded me that this was not something I had done solely through numerous posts on Apple Discussions. I imagine I likely spent time reading multiple posts here and elsewhere, uncovering the concensus (which i think is still a fair term) that it could not be done through Aperture*, could be through Finder, but was inadvisable.
*This is still accurate, afaik. You cannot delete the pair from a RAW+JPEG pair in Aperture. Exporting, then deleting in Finder, then reimporting is still not something "done in [entirely] Aperture."
Frank Caggiano wrote:
No one actually told you to delete anyting in in the Finder you came up with this yourself as your own solution
This comes from the critical mistake on my part of not making clear that I was paraphrasing multiple responses rather than saying "Bob told on a Monday that i should..." That is one huge mea culpa and I'd edit it if I could. To be clear, my comment that "it's probably not wise, but as far as I know, it won't have an adverse effect" is a paraphrase of multiple answers to the broad question dealing with how Aperture handles files that have been deleted in Finder. At the time, it was known that you could delete a file in Finder, that Aperture could be made to accept that, that it might cause issues further down the road, but that those issues were unkown. I paraphrased that but failed to make it clear that's what I was doing. Again, my apologies.
Frank Caggiano wrote:
So I'm not really sure what it is you are coming back here now to say? There was no 'consensus' to do this, it was your own 'solution'
In this respect, I think you've misunderstood me. At the time I made this post, I still was not seeing a direct connection between deleting files in Finder and adverse consequences in Aperture (or perhaps I should say my searches did not turn up such a connection). As such, I made this post to provide the community with clear evidence of why one should not delete one-of-a-pair files in Finder. Again, I may have simply missed the thread that detailed that to do so would result in a null error when relocating Masters. That said, in July 2013 I had been pulling my hair out trying to figure out why I was getting the null error and I did not see a thread that asked "have you deleted files in Finder" as a way to troubleshoot.
Hopefully, I've cleared up any confusion now. To bring this all back around to my original point for the thread, I intended it to (1) offer a more direct way to troubleshoot the null error on relocating Masters, and (2) to offer a cautionary tale for those who choose to delete one of the RAW+JPEG pair in Finder. There are better (though more time- and space-consuming) ways to get it done, and my original post should help demonstrate why.