Could not execute 'apt-key' to verify signature (is gnupg installed?)

[deivid]

After upgrading to 16.04 I'm getting this error for all my apt sources.

This seems different to both https://bugs.launchpad.net/ubuntu/+source/apt/+bug/1524196 (since I don't get the "Couldn't create tempfiles for splitting up /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_xenial-updates_InRelease" errors) and https://bugs.launchpad.net/ubuntu/+source/apt/+bug/1577926 (since apt-key run by itself fails too).

Downgrading to apt=1.0.10.2ubuntu2 fixed the problem so it seems to be related to recent changes in apt.

Thanks!

[deivid (deivid-rodriguez)]

Just tried upgrading apt again today and got the same errors. Reverted back again, but now to 1.0.10.2ubuntu3.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Steven Grimm (sgrimm)]

I ran into this today and the problem turned out to be /tmp:

# ls -ld /tmp
drwxrwxr-x 11 ubuntu ubuntu 4096 Aug 24 00:23 /tmp

This fixed it:

# chown root:root /tmp
# chmod 1777 /tmp

I don't know how /tmp got in that state on my server (it's a fairly fresh install of 16.04) but perhaps that's the underlying problem for other people too.

[deivid (deivid-rodriguez)]

@sgrimm Thanks for posting that. Unfortunately, I just had a look and my tmp folder permissions are fine.

[Falcon Taylor-Carter (falconertc)]

I'm having the same issue. Hopefully someone else has a recommendation.

[Marty Ellis (marty-ellis)]

My problem was caused by using vagrant. Vagrant sets the tmp owner to vagrant:vagrant. @sgrimm - I followed your advice and that resolved my issue.

[Falcon Taylor-Carter (falconertc)]

My issue turned out to be related to my infrastructure provider (DigitalOcean) not updating the kernel correctly.

[deivid (deivid-rodriguez)]

Thanks for the pointer @falconertc, that ended up being my problem as well. I solved it following the instructions posted here: https://bugs.launchpad.net/ubuntu/+source/apt/+bug/1577926/comments/18