Hi Neil, Quick reply your comment >> if deleting the old UID 501 user account has not deleted ALL files with >> owner 501 then the new account may be allocated a new UID (503) - I think >> this sort of situation is where you can see the “unknown” user when looking >> at permissions in finder.
This will happen if you have removed an account or group from the system, and still have files on the system that were previously associated with that account. This happens because the GID, UID, (user and group identifiers),or UUID (universally unique identifiers) number associated with the file cannot be matched to the proper account or group in the system. If the user or group is missing, the system will associate the file to “nobody” or “unknown,” but sometimes it may think the file belongs to another system account altogether, and associate it with that one. I'm working on a post about Owners / Groups / Permissions will port when I can put it together. Permissions are so interesting … and confusing at the same time ;-) Cheers, Ronni On 20/05/2010, at 10:39 AM, Neil Houghton wrote: > Hi Ronni, > > HeHe... Yes, I’ve always been wary of the “expert” tag – I used to work in an > industry with lots of “experts” and the standing joke was something about a > “spurt” being a drip under pressure and “ex” meaning has-been ;o) > > However, all on the list appreciate your experience and the time you put into > your (very comprehensive) answers to various problems. > > Yes, of course, either approach will require Adam to have a complete backup > of his old drive – and we agree that approach A is preferable, if more > time-consuming. > > It would be interesting to know just how approach B gets around the change of > UID – I always thought that “repair permissions” would just change the actual > read/write/execute permissions – I didn’t think it would change the UID. > > It occurs to me that a “B2” approach, that would cover this, would be to > create a temporary account to free up UID 501, eg: > > > B2. Steps 1 to 4 are additional steps to free-up UID 501, steps 5 to 10 are > basically as your original approach B: > Create a NEW temporary Administrator Account (should have UID 502) > 'Log out' of the OLD Administrator (wrong) Account (UID 501) > 'Log In' to the TEMP Account (UID 502) > DELETE the OLD Account (UID 501) > Create a NEW Administrator Account with exact details of the User Account > that you have on the backup drive (should be allocated UID 501, which is now > free) > 'Log out' of the TEMP Account. (UID 502) > 'Log In' to the NEW Administrator Account (UID 501) > DELETE the TEMP Account (UID 502) > Transfer your Data across from the Backup Drive. > > This should achieve the same as approach B but allow the new account to have > UID 501 > > One problem might be at step 5 – if deleting the old UID 501 user account has > not deleted ALL files with owner 501 then the new account may be allocated a > new UID (503) - I think this sort of situation is where you can see the > “unknown” user when looking at permissions in finder. > > Just my thoughts – as I say, I still find many aspects of permissions > confusing – I am basing the above on bits and pieces of my (failing) memory > from sorting out past problems I had. > > > > Cheers > > > > Neil > -- > Neil R. Houghton > Albany, Western Australia > Tel: +61 8 9841 6063 > Email: [email protected] > > > > > on 19/5/10 2:19 PM, Ronda Brown at [email protected] wrote: > >> Hi Neil, >> >> I have not been avoiding your questions, just time has not permitted me to >> answer as yet. I will get back with a more thorough answer to 'Permissions' >> in Snow Leopard when possible. Also I don't profess to be an expert on >> Permissions, I don't profess to be an expert in anything ;-) >> >> When you start up a brand new Mac, or start up after an Erase and Install, >> you will be asked if you want to migrate. >> That is the preferred time to migrate from your old Mac or backup to your >> New Mac or New Hard Drive. >> >> I would prefer Adam to do A. To do and Erase & clean Install of SL & then >> let Migration Assistant run & migrate everything across, which will bring >> his User Account / Settings & Files across. >> >> With way B. You DELETE the OLD (wrong) Administrator Account BEFORE you >> transfer the data across from the backup drive. >> This way, when you then 'Repair Permissions', the User should (hopefully) >> have the correct permissions on his data. >> I have done it this way before and I'm fairly sure the UID was 501 … At >> least I did not experience any permission problems. >> But, I'm open to anyone disagreeing with this. >> >> Of course neither of these ways will be possible if Adam doesn't have a >> complete backup of his old drive! >> >> Cheers, >> Ronni >> >> On 19/05/2010, at 10:47 AM, Neil Houghton wrote: >> >>> Hi Ronni & Adam, >>> >>> I have been following this with interest – I have had to sort out >>> permissions problems in the past, I generally get there in the end, but I >>> still find many aspects of permissions confusing. >>> >>> >>> I am hoping that Ronni could clarify how one area works: >>> >>> >>> I can see how approach A works – this is basically just like taking home a >>> new computer and migrating the data over from the old computer. >>> >>> With approach B, however how does the UID get back in sync – or does OSX >>> work around that? >>> >>> To elaborate on my query: >>> >>> It sounds like the old computer was set up with just the primary user >>> account, which would have had the default UID of 501 for the main account – >>> this is the account now on the back-up disk that we want to restore. >>> The technician set-up one main account on the new HD – which is therefore >>> also UID 501 – but with other details wrong (as per Adam’s id printout: >>>>> admins-imac:~ adam3$ id >>>>> uid=501(adam3) .............. >>> If Adam creates a NEW Administrator Account with exact details of the User >>> Account that he has on the backup drive it will presumably get a UID of 502 >>> (501 is already taken) - so the exact details may be the same but the UID >>> will be different. >>> When Adam DELETES the OLD Account – he is deleting the account currently >>> with UID 501. >>> >>> >>> So this is where I am unclear as to how things proceed: >>> >>> Would deleting account UID 501 result in the new account getting its UID >>> re-assigned from 502 to 501? or >>> Would migrating over the OLD account UID 501 result in the new account >>> getting its UID re-assigned from 502 to 501? or >>> Would the new account retain the UID 502 but the migrated files get their >>> ownership modified to suit this? or >>> I’m missing the point, what happens is ........ >>> >>> If the (new) main account has UID 502, would there be any problems at the >>> next migration to a new computer (with main account UID 501)? >>> >>> >>> Ronni, I hope you don’t mind me jumping in with these questions – but I >>> know that many of us find permissions intricacies somewhat confusing. >>> >>> >>> I know I had big problems in the past when I set up a new computer with an >>> account that was ALMOST the same as the old one! (I can’t remember now >>> whether the short names were the same but the user names different, or >>> vice-versa, or names the same but UIDs different) - I remember it was a >>> painful process sorting it out. >>> >>> >>> Cheers >>> >>> >>> >>> Neil > -- The WA Macintosh User Group Mailing List -- Archives - <http://www.wamug.org.au/mailinglist/archives.shtml> Guidelines - <http://www.wamug.org.au/mailinglist/guidelines.shtml> Unsubscribe - <mailto:[email protected]>
