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Recently I've been encountering a very annoying problem during my commute in which my laptop unexpectedly powers off. I am using a Dell Inspiron 15 with a touchscreen. The laptop is just a bit over a year old. Here are some more details:

  • Speed does not seem to matter. Today it has happened while moving in heavy traffic at approximately 5 km/h, on a road at 60 km/h, and down a rapid transit lane at nearly 100 km/h
  • It happens regardless of position inside the vehicle. Whether I'm sitting 15 feet back (closer to the front of the bus) or 40-60 feet back (last row of seats) it still happens.
  • It happens regardless of road quality. There's an on-ramp and some parts of the Transitway that have bad potholes but hitting those doesn't cause the power down, yet this has happened on some newly-paved roads.
  • Acceleration doesn't seem to matter either. I've encountered several instances of sudden braking that did not cause the power down.

To reduce vibration, I typically set the laptop on top of a nearly-empty backpack on my lap, without any part of the laptop touching the seat or vehicle directly.

Another thing I've noticed too is that this problem does not happen only on vehicles, but also when I am walking between classes. I usually put the computer to "Sleep" instead of shutting it down before putting it in my backpack. Sometimes when I open it up the next class or at work, the power would be off and my open documents/windows would have crashed. For now, I've enabled the "Hibernate" option and use it when class is over, but it still doesn't help me when using the system in transit.

This power down phenomenon never happens when the system has not physically moved.

I've checked the Event Viewer in Windows and nothing of significance shows up:

The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly.

The battery lock is in the lock position and it appears to be fairly secure in its position.

I've also looked at some other questions that did not help my case:

Can anyone suggest something to prevent this from happening?

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Many Dell laptops have a built in accelerometer to sense when a laptop is falling and can be configured to instantly turn off the hard drive to prevent damage on impact. It sounds like your accelerometer is too sensitive. I'm guessing there's probably a setting in the BIOS that will let you disable it. I'll do some research and post if I find anything specific.

UPDATE: Apparently there is a Freefall Sensor Driver. If you go to Dell support and put in your service tag, you can download the current driver.

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I went to and inputted my service tag but there is no such thing (or anything similar) when I clicked on "View all drivers". – rink.attendant.6 Jun 6 '14 at 1:29
There are about 30 different Dell Inspiron 15 models. What is your exact model number? Did you check the BIOS to see if there's anything you can toggle regarding an accelerometor or free fall sensor? Are you running Windows 7/8/8.1/32-bit/64-bit? – HighTechGeek Jun 6 '14 at 1:49
Inspiron 15R 5521 running Windows 8.1 64-bit and Linux Mint. – rink.attendant.6 Jun 6 '14 at 1:52
It looks like your model does have a Free Fall Sensor and many Dell computers use the ST Microelectronics drivers. Do you have this directory on your computer? c:/program files(x86)/STMicroelectronics – HighTechGeek Jun 6 '14 at 2:11
You may also want to check your Device Manager to see if the Free Fall Sensor is listed as an unknown device, or if it shows as being installed properly. (Hit Win+X and choose Device Manager from the pop-up list) – HighTechGeek Jun 6 '14 at 2:15

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