Mobile Home user cannot login

The content of /var/log/system.log is as followed (I just edited the username), but I can't really get a hint from it:

Sep 27 10:38:52 exp135 SecurityAgent[414]: User info context values set for myuser

Sep 27 10:38:52 exp135 SecurityAgent[414]: Login Window login proceeding

Sep 27 10:38:54 exp135 loginwindow[405]: Login Window - Returned from Security Agent

Sep 27 10:38:54 exp135 loginwindow[405]: USER_PROCESS: 405 console

Sep 27 10:38:55 exp135 ReportCrash[442]: DebugSymbols was unable to start a spotlight query: spotlight is not responding or disabled.

Sep 27 10:38:57 exp135 parentalcontrolsd[440]: CGSLookupServerRootPort: Failed to look up the port for "com.apple.windowserver.active" (1102)

Sep 27 10:38:57: --- last message repeated 1 time ---

Sep 27 10:38:57 exp135 com.apple.launchd[1] (com.apple.loginwindow[405]): Job appears to have crashed: Segmentation fault: 11

Sep 27 10:38:57 exp135 loginwindow[443]: Login Window Application Started

Sep 27 10:38:57 exp135 parentalcontrolsd[440]: CGSLookupServerRootPort: Failed to look up the port for "com.apple.windowserver.active" (1102)

Sep 27 10:38:57 exp135 loginwindow[443]: **DMPROXY** Found `/System/Library/CoreServices/DMProxy'.

Sep 27 10:38:57 exp135 loginwindow[443]: Login Window Started Security Agent

Sep 27 10:38:57 exp135 com.apple.launchctl.LoginWindow[447]: com.apple.findmymacmessenger: Already loaded

Sep 27 10:38:57 exp135 WindowServer[445]: kCGErrorFailure: Set a breakpoint @ CGErrorBreakpoint() to catch errors as they are logged.

Sep 27 10:38:57 exp135 loginwindow[443]: kCGErrorFailure: CGSPackagesGetWorkspaceType: couldn't get workspace type

Sep 27 10:38:57 exp135 loginwindow[443]: kCGErrorFailure: Set a breakpoint @ CGErrorBreakpoint() to catch errors as they are logged.

Sep 27 10:38:57 exp135 SecurityAgent[452]: Echo enabled

Sep 27 10:38:57 exp135 ReportCrash[442]: Saved crash report for loginwindow[405] version ??? (???) to /Library/Logs/DiagnosticReports/loginwindow_2011-09-27-103857_localhost.crash

Sep 27 10:38:58 exp135 ReportCrash[442]: Removing excessive log: /Library/Logs/DiagnosticReports/loginwindow_2011-09-25-122131_localhost.crash

Sep 27 10:38:58 exp135 SecurityAgent[452]: kCGErrorFailure: CGSPackagesGetWorkspaceType: couldn't get workspace type

Sep 27 10:38:58 exp135 SecurityAgent[452]: kCGErrorFailure: Set a breakpoint @ CGErrorBreakpoint() to catch errors as they are logged.

Sep 27 10:38:59 exp135 com.apple.launchd.peruser.92[427]: Background: Bug: launchd_core_logic.c:10063 (24984):0

Sep 27 10:38:59 exp135 com.apple.launchd.peruser.92[427]: Background: This API can only be used by a process running within an Aqua session.

Also a crashlog of loginwindow and HomeSync will be created. Both with

Exception Type: EXC_BAD_ACCESS (SIGSEGV)

Exception Codes: KERN_INVALID_ADDRESS at 0x000000000000001c

After contacting the support line and having a long phone call with them, we tried a variety of steps to fix the issue.

Turns out that, after deleting the home directory (on the client as well as on the server) the user is able to login again. However, the sync does not work. It will break with the error message that "(null)'s home directory can not be found. The home directory has to be created manually in the Workgroup Manager under the "Accounts" tab. Pick the user, select the tab "Home", chose the afp://.... link, push "Create Home Now" on the bottom of the window and Save. This will create the user's home directory and thus will be able to login and sync his home to the server.

This has worked for us so far for every user we encountered.