Hi. I'm struggling to turn off FileVault on Snow Leopard, 10.6.8. I have about 50 GB in my home folder, and plenty of spare disk space. Here's what I'm doing...

1) Go to System > Security > FileVault and click "Turn Off FileVault".

2) About 1 minute later I have to enter my password.

3) The "You are ready to turn off FileVault protection" box is displayed.

4) In this box I click "Turn Off FileVault" again. I am then almost immediately logged out. Is that what should happen?

How long should I expect to wait before I log in again? Will I be notified that the decryption is complete? I tried waiting for an hour and a half before logging back in, only to find that FileVault is still turned on.

When I check Console Messages, there are a bunch of error messages that look like they correspond to steps 1 and 4, above. These are:

Step 1:
02/08/2012 23:34:00 System Preferences[2609] ### Error:-5000 File:/SourceCache/Admin/Admin-478.6/FSUtilities.m Line:228
02/08/2012 23:34:00 System Preferences[2609] ### Error:-5000 File:/SourceCache/Admin/Admin-478.6/FSUtilities.m Line:228
02/08/2012 23:34:00 System Preferences[2609] ### Error:-5000 File:/SourceCache/Admin/Admin-478.6/FSUtilities.m Line:228

Step 4:
02/08/2012 23:35:21 com.apple.launchd.peruser.501[2518] (com.apple.AirPortBaseStationAgent[2543]) Exited: Killed
02/08/2012 23:35:21 [0x0-0x16f16f].com.hp.productresearch[2554] on write, error=-1
02/08/2012 23:35:21 [0x0-0x16f16f].com.hp.productresearch[2554] on write, error=-1
02/08/2012 23:35:21 [0x0-0x16f16f].com.hp.productresearch[2554] on write, error=-1
02/08/2012 23:35:22 com.hp.devicemonitor[2545] on write, error=-1
02/08/2012 23:35:22 com.hp.devicemonitor[2545] on write, error=-1
02/08/2012 23:35:23 com.apple.launchd[1] (com.apple.loginwindow[2485]) Job appears to have crashed: Bus error
02/08/2012 23:35:23 com.apple.launchd[1] (com.apple.loginwindow[2485]) Job exited before resuming per-user launchd for UID 501. Will forcibly resume.
02/08/2012 23:35:23 com.apple.ReportCrash.Root[2636] 2012-08-02 23:35:23.287 ReportCrash[2636:2903] Saved crash report for loginwindow[2485] version ??? (???) to /Library/Logs/DiagnosticReports/loginwindow_2012-08-02-233523_localhost.crash
02/08/2012 23:35:26 com.apple.WindowServer[2638] Thu Aug 2 23:35:26 Nicks-MacBook-Pro.local WindowServer[2638] <Error>: kCGErrorFailure: Set a breakpoint @ CGErrorBreakpoint() to catch errors as they are logged.

Any advice would be appreciated. Am I missing something obvious?