Solved trying to use bitlocker on a win 10 machine using win 8

[kkennyb]

TPM malfunctions on win 10 machine running win 8

i'm trying to run bitlocker on a windows 10 machine on which i've installed win 8.1 pro. you will see from the following screen shots messages,that this is not at all straight forward.

the top screen capture is when the lenovo was running its native windows 10 home,all is well with the TPM.

the second screen capture is when i've installed a licensed windows 8.1 pro onto the above mentioned lenovo,it shows that something is definitely wrong with the TPM,indeed when as prompted i tried to initialize the TPM,to try to take control of the device selecting the only option thats not greyed: out a warning pops up,please see the last screen capture.

the message reports that too many password attempts have been made,although zero passwords have been entered,either now or with other attempts i have also followed the instruction in the last message,several times, with no luck.

is this a problem caused because i've installed win 8.1 pro on a windows 10 machine and this has caused incompatibility, problems, that may not be possible to rectify ?



sorry for another confusing post,thank you for reading and for any assistance that may be given.

ken.

 

[kkennyb]

i was lucky to find the following solution found on a microsoft site and the person who had posted got it from somewhere else,it worked. i think the reason not many have had this problem is because it is a problem that only seems to affect machines purchased with win 10 on and then has then a fresh install of windows 8.1 pro,i don't think many people go down this route. hope it helps someone though

There's a discussion about this on SpiceWorks (sorry I cannot post links).
When you reimage the device and then attempt to enable BitLocker on this device you will get the error:
"The TPM is defending against dictionary attacks and is in a time-out period"
You cannot reset the TPM via the UI when the system is in this state.
Here is a solution. From an elevated PowerShell prompt run these three commands:
$tpm=get-wmiobject -class Win32_Tpm -namespace root\cimv2\security\microsofttpm
$tpm.DisableAutoProvisioning()
$tpm.SetPhysicalPresenceRequest(22)
Reboot your system and accept the prompt to clear the TPM data. You will now be able to encrypt the drive using the TPM chip.


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