cadamw
1 Nickel

Latitude e7470, Bitlocker triggered, TPM gone from Device Manager

Jump to solution

Hi,

I have a weird issue regarding Bitlocker and the TPM on Latitude e7470s running Windows 7 Ent.  I've had three laptops trigger Bitlocker on boot, we enter the key and boot into Windows 7 Ent.  We goto Bitlocker Drive Encryption Management to Suspend/Resume to reset and I receive an error message that a compatible TPM Module cannot be found.  When looking in Device Manager the TPM is gone. 

We start with a base Win 7 Ent image, and then I use Dell Command Update to install the drivers, including the Broadcom TPM Driver.  In my research I've read that if you don't have an entry for the TPM under "Security" then it might be listed under System.  It is not listed under System unless there is a code name for the module.  I've also read that you should use the Microsoft Drivers for the TPM and not the manufacturer's drivers, is that a true statement? 

We use Latitude 7440's, 7450s, and 7470s in our environment.  The issue is isolated to the 7470's only.

Has anyone else encountered this "disappearing TPM" issue before? 

Thanks for all of your help. 

0 Kudos
32 Replies

RE: Latitude e7470, Bitlocker triggered, TPM gone from Device Manager

Jump to solution

Thank you for posting.

If you haven't tried it already please update the BIOS to 1.5.3 or higher and check to see if the problem continues.  You may download 1.5.3 here.

Please let me know if this corrects the issue.

 

TB

Specialize in Laptops, Mobile Devices
#IWork4Dell

0 Kudos
cadamw
1 Nickel

RE: Latitude e7470, Bitlocker triggered, TPM gone from Device Manager

Jump to solution

Hi Terry,

Thanks for the prompt response.  I wasn't aware that a new BIOS had been released, so I will try that, but the update doesn't mention anything about the TPM specifically. 

I have about 15-ish of these Latitude 7470s already deployed into the field, but have only had issues with the three.  How will I know if the BIOS update is resolving the issue?  I mean, I understand that with weird behavior like this and an available updated BIOS the first steps should be to update the BIOS, but with no mention of my issue in the BIOS notes it's kind of like a "do this and see if it continues to happen" thing. 

What should I expect from updating the BIOS?  Will the OS detect new hardware and automatically install the Microsoft drivers for the TPM?  Will I need to reinstall the drivers from Broadcom for the TPM?  Will I need to decrypt/encrypt the HD again? 

Thanks for any additional information.

0 Kudos

RE: Latitude e7470, Bitlocker triggered, TPM gone from Device Manager

Jump to solution

My feeling that is what will happen, the system will all of a sudden be able to detect the TPM and BitLocker will function correctly.  If you continue to have issues with BitLocker

If you continue to have problems this document may help.  

Please let me know if you continue to have problems. 

TB

Specialize in Laptops, Mobile Devices
#IWork4Dell

0 Kudos
cadamw
1 Nickel

RE: Latitude e7470, Bitlocker triggered, TPM gone from Device Manager

Jump to solution

Hi,

So I've updated the BIOS to the latest (1.5.3) and the TPM is still not available within Windows 7.  When trying to "resume" protection I still receive the error that a compatible TPM module could not be found. I've ran Dell Command Update and the application is reporting that everything is up to date.  I've also ran Windows Update to ensure Windows is up to date. 

The TPM is listed in the BIOS as enabled and activated. 

Are there any other things that you could suggest I try?

Thanks!

0 Kudos

RE: Latitude e7470, Bitlocker triggered, TPM gone from Device Manager

Jump to solution

I will be shooting you a friend request, please accept it so that i can get the system information and possibly a solution. 

TB

Specialize in Laptops, Mobile Devices
#IWork4Dell

0 Kudos
cadamw
1 Nickel

RE: Latitude e7470, Bitlocker triggered, TPM gone from Device Manager

Jump to solution

I actually have a ticket open with Dell Premier Support.  They provided me with some steps to get the TPM recognized in Windows Device Manager.  I'm not sure if it's a temporary workaround or not.  I'm still awaiting that information, but here are the steps:

  1. Power off the laptop and remove any power adapters.
  2. Remove the rear cover (screws do not come out fully).
  3. Remove the SODIMM(s).
  4. Remove the battery (one screw, pull the tab to remove the battery connector from the board).
  5. Press and hold the power button for 20 seconds (to drain capacitors).
  6. Reinstall the SODIMM(s).
  7. Reconnect the battery and screw it down.
  8. Attach the rear cover.
  9. Power on the laptop, boot into windows, open Device Manager and verify the TPM is listed under Security Devices.

I have performed these steps on 1 of the 4 laptops that were demonstrating this issue and it restored the TPM to Device Manager. I was also able to resume Bitlocker with no issues.

RE: Latitude e7470, Bitlocker triggered, TPM gone from Device Manager

Jump to solution

I had a similar issue with my E7470. The TPM was gone from Windows Device Manager AND from BIOS. Needed a motherboard swap. Now I'm having other TPM issues where after some sleep/resume cycles, the TPM stops responding. It at least comes back after a reboot.

Makes me wonder if another BIOS update is needed or a new TPM driver.

0 Kudos
trevailious
1 Copper

RE: Latitude e7470, Bitlocker triggered, TPM gone from Device Manager

Jump to solution

Glad to find others posting about this issue.

I am having this same disappearing TPM issue on several Dell Latitude E7470 laptops. BitLocker is enabled on these laptops and it uses the TPM.

One laptop in particular, which uses Windows 10, just had this exact issue for the second, perhaps third time over the weekend. This issue previously happened and I updated the the BIOS to version 1.5.3. The BIOS flash caused the TPM to reappear and BitLocker was able to function, however the issue has reoccurred again.

I am going to follow the recommended document asap and see if this helps.

0 Kudos

RE: Latitude e7470, Bitlocker triggered, TPM gone from Device Manager

Jump to solution

One of the steps is to reinstall Windows. That will not help with the TPM doesn't even show up in the BIOS.

0 Kudos