My understanding is that since plists in /Users/artie/Library/Preferences/ByHost are identified by alphanumeric strings unique to the logic board of the computer on which they were created those with strings that harken back to my old deuced Mac(hina) are no longer of any consequence and can be deleted.

With that in mind, I've gone through the folder and deleted all plists with the same names as new ones but with old strings, but I've still got these uniquely named plists with old strings. (From their modification dates, the top two look like they maaay have been modified on my new MBP, which I don't think is possible.)

com.apple.loginwindow.DE053930-6431-5243-ABA3-C9AACEDD1307.plist
com.apple.iTunes.DE053930-6431-5243-ABA3-C9AACEDD1307.plist
com.apple.syncservices.DE053930-6431-5243-ABA3-C9AACEDD1307.plist
com.apple.ScreenSaver.iLifeSlideShows.DE053930-6431-5243-ABA3-C9AACEDD1307.plist
com.apple.systempreferences.DE053930-6431-5243-ABA3-C9AACEDD1307.plist
com.apple.HIToolbox.DE053930-6431-5243-ABA3-C9AACEDD1307.plist
com.apple.iCal.helper.DE053930-6431-5243-ABA3-C9AACEDD1307.plist
com.apple.scheduler.DE053930-6431-5243-ABA3-C9AACEDD1307.plist
com.apple.AddressBook.sync.DE053930-6431-5243-ABA3-C9AACEDD1307.plist
com.apple.screensaver.SSILifeMediaType/iPhoto/iPhoto.iPhotoAlbumSaver.DE053930-6431-5243-ABA3-C9AACEDD1307.plist
com.apple.SoftwareUpdate.DE053930-6431-5243-ABA3-C9AACEDD1307.plist
com.apple.preference.internet.DE053930-6431-5243-ABA3-C9AACEDD1307.plist
com.apple.Image_Capture.DE053930-6431-5243-ABA3-C9AACEDD1307.plist

Is it safe to delete them?

Thanks.

yep ByHost is part of the reason macs are so good with moving the hdd to another physical machine and booting off it. Machine-specific settings (like energy saver) are stored there and are customized for each computer. Though the reason why an app needs to store something ByHost can often be a mystery.

Those files, like most mac preferences, are created as needed when missing, so it's almost always ok to remove them. If you know for certain you don't own the machine they apply to anymore, it's definitely safe to remove them. But they're usually small and really not worth your effort?

You can sort ByHost folder by date modified and the current machine's entries should be on top. Anything below that might be fair game.

Even if you delete something your current computer is using, it'll just remake it, and you may find a setting or two somewhere has changed from the value you customized it to, back to its default value as the ByHost file is recreated automatically.

BTW, that folder is normally hidden isn't it? That's Apple's way of saying "no touchie!"

As I thought; thanks for confirming that I can delete those files with impunity.

I've always been pretty neurotic about /Users/artie/Library/Preferences, keeping track of new plists and deleting old ones when they're no longer needed. (I talk to people who've got an incredible number of plists, many for apps and processes no longer in use, and others with no known purpose [at the moment].)


Apple tried "no touchie", and judging by the relative ease with which it's now overcome it obviously didn't get a very warm response. (I don't know about you or others, but I visit my home folder many times every day and wouldn't care to have to "Go" to it.)

I'd caution you, not all of those files recreate normally. Most notably are network adapter lists. It's really annoying to open the network prefs panel and find you not only don't have an ethernet port, but there aren't any listed to add back when you click [+]

Thanks, but by "those files" I meant the ones with the old logic board's ID, every one of which I've deleted with no repercussions.