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5 Posts
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59108
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.
Kappa Kappa Gam
3 Posts
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November 10th, 2017 06:00
All our e5470's refuse to work with a m.2 drive. Even the Windows 10 installation fails during the install. If you image the drive beforehand and put it in it will boot up and then blue screen. Sometimes safe mode buys you some more time but you'll still blue screen. I think I have narrowed it down to the TPM module. However disabling the TPM doesn't resolve it. I've had to send in the laptop, Dell replaces the motherboard and sends back and then have to update the TPM firmware and now it seems to be more stable.
All our OptiPlex 5040's work fine with TPM and the same m.2 drives. All the e5450's work fine with TPM on although these machines are Win 7.
CChaney317
1 Message
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January 4th, 2018 14:00
Hi,
We have tried all the steps suggested and still no joy. TPM does not show in the BIOS or Device Manager. Short of having the mother board replaced, are there any other steps that can be taken?
This has happened on other E7470 laptops we have, but the issue has been resolved with removing the laptop from the power supply, holding the power button for 30 seconds and turning the laptop back on.
Any help would be greatly appreciated.
Thank you.