OK. I've taken a deep breath and counted to 10, well, actually to 100 because this is such a ridiculous issue that I feel Apple developers and s/ware testers are a bunch of King Canutes for not noticing this problem lapping around their feet. Here's the issue, as best I can describe it after the best part of a bottle of prime vin rouge. Issue: Mail cannot tell the difference between upper and lowercase alpha chars in Mailbox names. 1) I have Mailboxes in Mail with sub-Mailboxes. I decide that, when expanded, the root Mailboxes are not obvious enough and decide to rename them in caps. 2) I rename 'Reference', 'REFERENCE'. I receive an error dialog to the effect of: 'You already have a Mailbox named Reference.' I think - no I don't, upper and lower case alphas are different chars. 3) I acknowledge the dialog and find I now have two Mailboxes, one called 'Reference' and one called 'REFERENCE'. They both have the same set of sub-Mailboxes. 4) Assured that they contain the same sub-Mailboxes I delete 'References'. 5) I now look in 'REFERENCES' and find that it has no sub-Mailboxes. <start cursing>, though all the 'Reference' level emails are still present. 6) Spotlight search highlights that I have a REFERENCES.mbox folder that seems to contain some [just realises his Apple keyboard has no hash key - the Canutes] ????.emix files and an info.plist file. No References.mbox I'd be grateful if anyone knows how I can retrieve my original folder structure? Thanks. Being inexperienced in the world of Apple defects I would welcome an opinion as to whether or not this is worth submitting to Apple. Certainly seems it to me. AN ASIDE As a returner to Macs after seven years in the hinterland due to professional commitments I have to say that, on the whole, I have been delighted. I find enjoy using computers again. Sadly, and speaking in my professional capacity as a s/ware tester, this issue has incompetence crudely scrawled all over it. I am astounded that it exists and, much as I am loathe to say it, this wouldn't have been a problem in Outlook on XP - I know, I've done the same thing; trust me on this. TIA for any advice Ed PS Please, where IS the hash key? PPS Don't you hate it when you get your thread name wrong and can't change it. Doh!