I have a Lenovo Thinkpad Carbon X1 which has started to misbehave recently. The basic symptoms are that it
- Can't be relied upon to start when pressing the power button (not sure if it never does, or if it just mostly doesn't)
- Usually starts by itself if I plug in the power coord when it's turned off (again, can't be sure if this always happens or just mostly)
- Displays the following message upon startup:
System CMOS Checksum Bad - Default settings used
Real Time Clock Error - check time and date settingsPres F1 to edit settings, or Esc to continue
If I press F1 and change the date in BIOS to something remotely reasonable (usually I just change the year to 2015 and leave the rest unchanged) it reboots twice when I hit F10 for save and exit, and then starts normally.
If I press Esc, I'm presented with the same message, minus the first row (i.e. only the real-time clock error). I can then either change the date (as above) or press Esc again, and have the computer reboot again and then start normally.
I have fiddled with the BIOS settings, because I'm dual-booting Windows 8 and Ubuntu 14.04, and to make it boot into GRUB2 rather than the Windows Boot Manager, I had to change some settings related to UEFI/Legacy boot. I had this working for the better part of the past fall, but all my settings were reset when Lenovo pushed a BIOS update a couple of weeks ago so I had to re-fiddle. I can't remember if I had seen this behavior before or after that (yes, I really should have asked this question immediately instead of fiddling around to see if I could fix it...)
The symptoms show up regardless of, and are from what I can tell unaffected by, which OS I booted last.
If there is any other information I can get that would be helpful, please ask in the comments. I don't know enough of this to know exactly what is relevant, or how to troubleshoot (more than trial-and-error, which hasn't worked so far...).