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1 Copper

XPS 15 9550 - TPM has "disappeared"

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After receiving my XPS 15 9550 about six weeks ago I immediately activated BitLocker w/TPM. That was working fine until about one week ago; I was suddenly prompted for the BL Recovery Key after having had the laptop shut down for about 24 hrs.   

Consecutive reboots kept asking for the recovery key. Eventually I tried suspending the BL protection. Upon trying to resume it I got the error message that "no TPM security device was found on on this computer". And sure enough: The TPM had been set as a "hidden device" under Device Manager, trying to re-enable it led to the same error message. Furthermore I was unable to find any mention of TPM in the BIOS.

No hardware changes or BIOS upgrades had been performed when this problem occurred. 

I just now tried to upgrade from BIOS version 1.2.0 to 1.2.2 (latest), but with no luck - the TPM is still missing from the BIOS. I've also tried to restore to factory settings, but with the same result.

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IndexOverflow
1 Copper

RE: XPS 15 9550 - TPM has "disappeared"

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I finally got a hold of a Dell technician who was able to understand my problem. I was told to do a power cycle of the laptop: Remove the battery, remove the memory sticks and finally press the power button for a good 30 seconds. Then wait another 30 seconds before you put everything back together. 

In another words, just a full CMOS reset. But it worked! After booting the TPM options were back in "Security" in the BIOS. 

I still would really have liked to know what caused this in the first place though.

jsmithbmn
1 Nickel

RE: XPS 15 9550 - TPM has "disappeared"

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I also talked to a Dell technician about this problem. He suggested something much more easier:

Instead of removing RAM, Battery, ... you can easily reset BIOS by removing the power plug, pressing CTRL + ESC and insert the power plug (now the laptop should start automatically). With this combination, a BIOS reset is done. Afterwards my TPM module was visible (again). Hope this helps (and I hope I remember the key combinations correctly, but this should be the case).

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8 Krypton

RE: XPS 15 9550 - TPM has "disappeared"

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Call Dell -- the mainboard will be replaced under warranty.

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evasec
1 Copper

RE: XPS 15 9550 - TPM has "disappeared"

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I had the same symptoms when upgrading from 1.1.15 to 1.2.0 and the only way I could resolve it was to:

1) Enter the recovery and back up everything you need (i.e. prepare for a fresh install).

2) Roll back to the old BIOS (for me it was 1.1.15) - which should make your TPM re-appear.

3) Re-install a fresh copy of windows.

4) Upgrade your bios to the latest version.

5) Check that the TPM can still be seen.

6) Encrypt again.

It worked for me and might work for you. I just hope I don't have to do it for every BIOS update!

IndexOverflow
1 Copper

RE: XPS 15 9550 - TPM has "disappeared"

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Thanks for your reply. I'm actually having a hard time locating the previous BIOS versions, any suggestions? The support page for the laptop only lists the latest. 

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Ed_Luck
1 Copper

RE: XPS 15 9550 - TPM has "disappeared"

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This just happened to  my XPS 15 9550 as well.  I had BitLocker enabled using the TPM since June 2016.  I used the laptop over the weekend just gone and when I turned it on this morning (Monday 1st August) the TPM was gone and I had to enter the BitLocker recovery key.

I tried updating to BIOS 1.2.10 and nothing changed.  I also tried reverting to BIOS 1.1.15 and it still did not work.

I honestly suspect Dell has forcibly disabled the TPM chip in this device due to accidentally enabling it when they did not intend to do so in the first place as it is not a "business" device.  This seriously pisses me off because I use it for work and part of the reason I bought it was because I knew TPM worked (after checking other owners for their experiences).

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evasec
1 Copper

RE: XPS 15 9550 - TPM has "disappeared"

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It took me a couple of goes reflashing BiOS the first time it threw an error but the second time it went through. I think I also had Bitlocker Protection Paused when I did it. I've since found an (obscure) Dell page that tells you you have to Pause Bitlocker any time you upgrade BIOS. God knows why their utility doesn't do this for you automatically when updating!

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evasec
1 Copper

RE: XPS 15 9550 - TPM has "disappeared"

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evasec
1 Copper

RE: XPS 15 9550 - TPM has "disappeared"

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praines
1 Copper

RE: XPS 15 9550 - TPM has "disappeared"

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Here is my experience just today.  I have a XPS 15 9550.  Got the Dell Update Utility message to update the BIOS.  I went, "sure go ahead".  Looked like it worked fine but when it came time to boot Windows all I got was a blank blue screen for about 1 min then the laptop just turns off.

I tried changing the Boot Mode to UEFI with Secure Boot off but no help

I booted off my recover USB flash drive I luckily made.  Startup Repair failed.  Restore Point failed.

I final thought of Bitlocker being an issue and brought up the Command Prompt and use manage-bde to decrypt the drive.  ***.  It now boots.

I then re-encrypted with BL and rebooted several times and it works.   Then I remembered Secure Boot was off so I turned it back on.  Now it will not boot again.  

I turned Secure Boot back off and booted.  Then decrypted the drive again.  Then rebooted with Secure Boot on.  It worked.  I re-encrypted with Secure Boot on and then rebooted.  Now all works again as expected.

My guess is the BIOS update is wiping the TPM.

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Ed_Luck
1 Copper

RE: XPS 15 9550 - TPM has "disappeared"

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Sorry guys but none of these posts are helping.  I had no issues flashing the BIOS either back to 1.1.15 or back up to 1.2.10.  The problem is that the TPM hardware device is GONE from Device Manager.  Without the TPM, BitLocker won't encrypt the drive.

If I go into Device Manager there is no "Security Devices" item in the list, which is where the TPM chip was previously.

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