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Latitude e7470, Bitlocker triggered, TPM gone from Device Manager
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.
cadamw
5 Posts
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June 23rd, 2016 17:00
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:
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.
cadamw
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June 13th, 2016 13:00
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.
DELL-Terry B
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June 13th, 2016 13:00
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
DELL-Terry B
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June 13th, 2016 16:00
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
cadamw
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June 21st, 2016 13:00
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!
DELL-Terry B
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June 23rd, 2016 17:00
I will be shooting you a friend request, please accept it so that i can get the system information and possibly a solution.
TB
mark.valpreda
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June 26th, 2016 08:00
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.
trevailious
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June 28th, 2016 18:00
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.
mark.valpreda
47 Posts
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June 29th, 2016 08:00
One of the steps is to reinstall Windows. That will not help with the TPM doesn't even show up in the BIOS.
DELL-Terry B
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June 29th, 2016 10:00
Please let me know if you continue to have problems with the TPM or Bitlocker.
TB
mark.valpreda
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June 29th, 2016 10:00
Terry- I am and so is trevailious!
cadamw
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June 29th, 2016 14:00
** Dell Support Update **
This is a temporary workaround until they can determine the root cause of the issue. I'll update as I know more.
prometa
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August 6th, 2016 19:00
I am having a similar issue with a Mobile Precision 5510, though the issue only showed up after installing the Windows 10 Anniversary Update. If the machine sleeps, on wake the TPM will be gone and the machine will force reboot. On next boot, the machine will not detect the TPM.
If I shutdown (which apparently preserves the kernel image), on next boot the TPM will also be gone, but if I reboot (which clears the kernel image), the TPM will return.
I've already updated to TPM2.0, but that did not solve the problem.
It's unclear at this point whether the issue is Windows issuing improper commands or a bug in the TPM firmware, but it has totally disabled sleep on this machine, as well as prevented me from using bitlocker.
yes34567
2 Posts
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October 6th, 2016 08:00
I just purchased a E7470 and after two days of use the TPM feature is no longer recognized by the computer as well. I have updated the BIOS to the current version but that didn't fix the issue. Since this seems to be a common issue is there any permanent fix being worked on?
Lucassantos
1 Message
1
October 27th, 2016 04:00
Hi
Im having the same issue as well with our E7470s. SSD has been previously encrypted with BitLocker, but now the TPM module is missing from the BIOS. Have trying flashing the BIOS, updating, etc. but no change. Work around is to suspend encryption which is not ideal on an enterprise environment with sensitive data :(