UEFI ERROR: Verification failed (15) Access Denied

[blankenberg]

Since today when I start or restart my PC I immediately get a blue screen which says:

Verification failed: (15) Access Denied

I press return to enter "OK" and get another blue screen called "Shim UEFI key management".

I am given 3 options: Continue boot; Enroll key from disk; Enroll hash from disk

If I select enroll key/hash I get a long list - I've tried selecting some of them but the key cannot be found [message: Only DER encoded certificate (*.cer/der/crt) is supported].

If I select continue boot I boot directly into Windows 8.1 (64-bit) despite my system being dual-boot with a Linux distribution (and working with both Linux and Windows perfectly well until today). Every time I boot or reboot I have to go through this same sequence and can only boot Windows.

Possiblly important additional info:

1) I have been invited to upgrade to Windows 10 but have not done so yet - I'm "hiding" the 8.1-> 10 upgrade option;

2) yesterday (i.e. just before this problem appeared) the HP Support Assistant updated "HP PC Hardware Diagnostics UEFI" to version 5.8.2.0

Has any UEFI expert any tips to overcome this Access Denied problem and/or tell me how to enroll the key which appears to be lost for some mysterious reason?

Many thanks.

[Big_Dave · Accepted solution]

Hi,

Sounds like you have a GRUB issue which there is little support for on this forum.  You might try the Linux forum.