"Require Installation Of Untrusted Packages" while upgrading with the update manager
Solution 1:
-
Write in a terminal:
sudo apt-get update && sudo apt-get upgradeor edit Update Manager settings (try this first if you have already configured Update Manager).
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Launch Update Manager and try again.
Running update through a terminal gives option whether to allow or disallow untrusted packages.
WARNING: The following packages cannot be authenticated!
playonlinux
Install these packages without verification [y/N]?
If you trust the package source, type y.
Solution 2:
This happens due to the missing of some GPG keys. To fix this , Open a terminal and run the below commands:
sudo apt-get update
You will get an error saying that some public key is not available. Note the key string ( after the NO_PUBKEY; eg:D6B6DB186A68F637 )
gpg --keyserver keyserver.ubuntu.com --recv XXXXX
Replace the XXXXX with the key string
eg : gpg --keyserver keyserver.ubuntu.com --recv D6B6DB186A68F637
gpg --export --armor XXXXX | sudo apt-key add -
eg: gpg --export --armor D6B6DB186A68F637 | sudo apt-key add -
sudo apt-get update
Now try updating your system again.
Here is a similar post: "Requires to install untrusted updates" Error in Update Manager
Hope this helps.
Solution 3:
You can install it via the command line: sudo apt-get install --allow-unauthenticated exiv2.
To permanently "trust" the repo, execute this: sudo apt-add-repository ppa:pmjdebruijn/darktable-release && sudo apt-get update. I believe that is the PPA you are using.
Solution 4:
In answer to your question, you cannot "fix" the GUI update (i.e. Update Manager), because it is apparent that that application does not currently have the capability of installing untrusted packages. If you want to install untrusted packages, you must do it at the command line.
There are, however, two ways you can stop Update Manager from reporting this error: either remove the untrusted software from your system OR trust the repository in question, as outlined in the answer to the other question ( Updates don't install because of "untrusted packages" ).
The first step is to find out which repository is causing the problem. You can find this out by typing apt-cache policy ambiance-colors at the command line.
However, a quick google reveals that ambiance-colors and radiance-colors are from ppa:ravefinity-project. So you should be able to fix your problem by typing
sudo add-apt-repository ppa:ravefinity-project/ppa
sudo apt-get update
sudo apt-get install ambiance-colors radiance-colors
taken from http://www.webupd8.org/2012/01/ambiance-and-radiance-colors-theme-pack.html