MarkusRising

Q: Windows 8 shut down unexpectedly and loads OS X Installer from connected Time Machine Drive

Hi everyone,

 

Quick History:

I recently ordered an iMac 21.5" (Late 2013) from the refurb store, and it's been a serious headache getting it up and running to do everything I require of it. The main task was set up a Windows partition (I'm a software developer and need access to Visual Studio). Initially, it wouldn't accept Windows 7 from a USB drive (issues with the installer and USB3, as I understand it). I eventually moved on from that concern and installed Windows 8, then upgraded same-day to Windows 10. Win10 had an issue with the graphics card and would not stop throwing kernel panics (Blue Screen of Death), so I gave up on that two days later and reverted to Windows 8. Since then, I've downloaded all of my updates, configured the PC as needed, and everything's been alright while I'm using it. Only concern is that it's a touch slow, but I've chalked it up to being issues with a 5400rpm drive, and my being used to the SSD from a Retina MBP.

 

The Issue:

As the overly-long title of my question states, the computer will sporadically shut down overnight, and reboot itself. However, it reboots to the OS X installer located on my connected external hard drive. I've made sure that the Startup Disk setting is set to the Boot Camp partition, and verified that on a manual restart (software, not the power button), it reboots into Windows normally and nicely. Now, despite the fact that I write software for a living on a Windows platform, most of my tech-centric abilities are from OS X. When I'm on Windows, 99% of my activity is work in Visual Studio, using MSOffice, or web browsing (on Chrome, not that it should make a huge difference). I've looked around a little bit at the Event Viewer (eventvwr.msc), and found the log entry that stated that the computer shut down because of a problem. No error codes, nothing noteworthy to go on at all, save for some Hex Codes/Words/Blocks that I haven't (yet) taken the time to translate and hunt down further.

 

The Real Question(s):

1) How can I go more in-depth to understanding why the computer is shutting down? It happened around 4:00am, and there were no updates scheduled for installation.

 

2) Can anyone explain the curious change to the boot selector? There's a file in the root level of the ExHDD called "tmbootpicker.efi" (hidden file when in OS X, appears in Win8 file structure), and I'm going to be looking into that next. I'd be happy to delete it if that's going to be my main problem, but would rather leave it alone if it'll mess around with the Time Machine backups I use the drive for (it backs up both iMac and rMBP).

 

3) [Optional] If anybody's had a similar issue with troubles upgrading to Win10 on this particular model of computer (Intel Iris Pro 5200 graphics card), I'd love to hear about their fix (if any). There was another question on the homepage of this discussion board that I'll take a look at shortly. Will edit this question out if I manage to solve it.

 

Thanks!

iMac (21.5-inch, Late 2013), Windows 8

Posted on Feb 23, 2016 9:25 AM