The following options are available to change the language of the default mailbox folders after mailbox initialization:
1. User runs Outlook with parameter: outlook.exe /resetfoldernames
2. User changes default folder language from within OWA: Options, Regional Settings, Rename default folders so their names match the specified language
3. Admin (Exchange 2010 only): Set-MailboxRegionalConfiguration mbx -Language xx-XX -DateFormat "d-M-yyyy"-LocalizeDefaultFolderName:$true
Language examples: nl-NL, en-US
Some time ago I did a GroupWise to Exchange 2007 migration with Quest Migration Manager for Exchange. I ran into one issue:
I had created 1000 mailboxes in one Exchange database which would be accessed with Outlook 2007 Dutch client. Before starting the mailbox migration from GW to E2K7 I distributed the mailboxes over 4 E2K7 databases with a mailbox move.
After migrating a mailbox I saw english mailbox folders under Outlook 2007 Dutch client. The following happened: move mailbox process created new mailboxes and moved the contents from the empty source mailbox. This resulted in default english mailbox folders. The solution was simple: first create mailboxes and distribute them directly over the 4 databases. Then perform mailbox migration from GroupWise to Exchange. Then access mailbox with OL 2007 Dutch client: only Dutch mailbox folders.
I've tested a mailbox move with Exchange 2010 SP1:
1. Create mailbox (no access with OWA/Outlook)
2. Move mailbox to another database
3. Access mailbox with Outlook 2007 Dutch client: default mailbox folders in English language
4. Set-MailboxRegionalConfiguration mailbox -Language nl-NL -DateFormat "d-m-yyyy"-LocalizeDefaultFolderName:$true
This step can be performed while Outlook is online and results in default mailbox folders in Dutch language.
So, a mailbox move initializes a mailbox which results in default mailbox folders in English language. Maybe Microsoft can build in an extra check? Mailbox move process should not move mailboxes which have not been initialized. Just delete and recreate is sufficient in this case. I have reported this ‘issue’ to Microsoft.