Windows 8: felled by a modem driver

tl;dr: if you can’t read the BSOD message or need to examine the minidump files generated by Windows when it crashes, use the BlueScreenView utility to view them. Windows 8 kept crashing on shutdown for me because of an errant 56K modem driver. Sad—so sad—but true.

My Windows 8 installation went off with just one hitch: the machine crashed on shutdown. Every. Single. Time. This made it impossible to use the hibernation feature, which was a blocker issue for a laptop.

So, how to solve the issue? Well, the first step is to read the error message, right? In this case, the crash was a Blue Screen of Death (BSOD) so you can’t copy the message or take a screenshot of it. You can take a picture if you’re quick on the draw: for the last several versions, Windows has been extremely shy about crashing and will hurriedly restart before the user even realizes what has happened.

Picture of a Windows 8 BSODThat means you have to be fast to read the message, but it used to be possible. With Windows 8, though, the BSOD message has been improved to show a little sad face and a message that tells the user that Windows is gathering information related to the crash and will restart shortly. In the example to the right, you can see that the small text reads HAL_INITIALIZATION_FAILED. In the example, though, the error message takes up the whole screen; in my case, the blue area was limited to a 640x480 block in the center and the fine print had been scaled down into illegibility.

That tiny bit of text holds the salient nugget of information that can help a veteran Windows user solve the problem. This was, needless to say, quite frustrating. The Event Viewer showed nothing, which wasn’t unusual in the case of a full system crash—how would it be able to write an error message?

The system would still boot up fine and was perfectly usable, so I could search for help in finding that elusive message. Every halfway-useful page I found quickly ended in a forum moderator instructing users to upload their “minidump” files so that a Microsoft employee could examine them.

That wasn’t acceptable, so I searched for help on how to read mini-dump files myself. Microsoft’s instructions ran to multiple steps and installation of low-level debugging software. Frustrated, I jumped into a conversation called Blue Screen error delivers unreadable instructions (font too small); how to increase fontsize in Blue Screen? which also featured an unhelpful answer. Luckily, someone responded almost immediately with a tip to use the BlueScreenView to read mini-dump files.

Within seconds I’d found out that my crashes were caused by a driver file called CAX_CNXT.sys. A few more seconds and I’d found out that this was the driver for the 56K modem on my laptop. I disabled that device with extreme prejudice and restarted the machine. No crash. Problem solved. It took longer than it had to, but now my machine has been running stably on Windows 8 for days. And lacking a modem driver hasn’t affected my workflow at all.