POST freeze on AHCI SATA Device Enumeration
Posted on 2011-10-14
The following has so far happened to two PCs that had different makes of motherboard and different Intel CPUs and different hard drives.
1. PC running Windows 7 SP1 x64
2. 1TB SATA Hard drive *using AHCI* partitioned as follows:
- Windows 7 System Partition (Primary) - no drive letter
- Windows OS Partition (Primary) - C
- Apps Partition (Primary) - D
- 3 or more data partitions (Logical) - E etc
3. Also a SATA DVD or BluRay drive.
4. Shrink some space off the front of the first logical partition using third party partitioning software.
5. Extend the apps partition into this now unallocated space using the same software.
On subsequent reboot, the PC freezes during AHCI POST and it is not possible to enter BIOS or bring up a boot device menu.
If I disconnect the SATA cable I can then get at BIOS etc. If I then set the SATA mode to IDE instead of AHCI the system now boots fine but I've now lost access to AHCI on this system.
Please note the freeze is occuring before the drive even boots so this is not the issue regarding the MSAHCI service in Windows.
What can have gone wrong that causes the AHCI BIOS to freeze when querying this drive and yet in IDE mode the thing boots normally and the partitions look healthy (and resized)?
(I know I could just "diskpart clean" the disk and start over to get AHCI back but I don't want to do that. I would though like to find out what has gone wrong here.)
Does the fault lie with the MBR or the partition table or elsewhere? How can I look into this? Is there a way to safely grab a dump of the partition table and/or MBR and would I stand any chance of debugging it at all if I could? Thanks!