Description of problem:

after preupgrade to fc16 system doent complete the startup process .

left with frownyface computer generic error and if go to tty console get repeating (seemed like every several seconds but may have been 30s or 1m) 
spam about a devices cache determination.

during a few trials of preupgrade from fc15 to fc16
was left with a system that seemed to go through the preupgrade process ok
but after the final reboot to what should be the f16 system
the boot process is halted just before login with approximately:
  
   <frowny_face monitor graphic on black screen>
   'Oh No! Something has gone wrong.'
   'A problem has occurred and the system cant recover.'
 
 lol, and oh and the best part of the overly nondescript error is next ;')

   'Please contact your system administrator.'

 ( facepalm, i always hated that error lol.  
   ok i notified myself.  have a cookie. :') )

when <ctl><alt><functionkey> to a nonfrozen tty and log in 
found:

  dmesg:    
     superblock last mount time is in future
     scsi 8:0:0:0 direct access generic multicard 1.00 pg:0 ansi:0 ccs
     sd 8:0:0:0: attached scsi generic sg2 type 0
     sd 8:0:0:0: [sdb] attached scsi removeable disk
     sd 8:0:0:0: [sdb] Test WP failed, assume write enabled
     sd 8:0:0:0: [sdb] Asking for cache data failed
     sd 8:0:0:0: [sdb] Assuming drive cache: write through

  .xsession-errors:
     gdu-notification-daemon: 1607 : libgdu-WARNING***: 
       unhandled property 'DeviceAutomountHint'

the errors reflected by these fragments seemed to repeat quite often in the respective logs:

     sd 8:0:0:0: [sdb] Asking for cache data failed
     sd 8:0:0:0: [sdb] Assuming drive cache: write through

     gdu-notification-daemon: 1607 ...

i dont know if grubby started the whole thing or not but there was an update.log entry that went something like:

  grubby fatal error: unable to find suitable template.
  grubby: doing this would leave no kernel entries.  not writing out new config.

thats about all the errors i can remember now.

Version-Release number of selected component (if applicable):

  fc16 after running fc15-preupgrade

How reproducible:

  only tried on a few machines before just went to clean installing but the few times i tried it gave the errors.

Steps to Reproduce:
1. fully update fc15
2. run preupgrade from fc15 including reboot to complete the install
3. reboot again and wait for login screen
4. after verne submarine splash shows but before the login prompt appears get frowny face error. :'(
  
Actual results:

  frowny face computer just before login prompt, frozen main interface window.

Expected results:

  smiley face computer, login prompt, successful login, fun ensues.

Additional info:

sure seems like a system clock issue or that its trying to reload a cardreader as a drive every few seconds.

sorry for the vague approximations of errors, going by memory.

found several related pieces relating to various of the error messages including the system time complaint but none of the suggested workarounds seem to work.  

i dont remember many of the threads but some of the suggestions were related to
   gsettings-date-convert, .gconf, .gconfd, 
   /etc/xdg/autostart, .config/autostart, 
   .gnome2

the error messages are roughly reproduced by hand as i didnt pull off the log files in the times that it happened since i needed machines up.  

i expect that unless others have similar issues that this i will probably close this because of insufficient info.