Unable to install CMake as not supported

I’m trying to download CMake from the software center where its source is listed as pureos-green-main but I get an error ‘unable to install CMake as not supported’ when trying to download & install it. Is this right? I need CMake to compile an R package, nloptr, it seems.

Hi @fredbastiat,

Is your system up-to-date? See the wiki entry about performing a system update.

If it is already up to-date, can you paste here the error message you get?

I went to the wiki and tried the instructions.

sudo apt update gives me an error message too:

‘Err:6 http://mirrordirector.raspbian.org/raspbian stretch InRelease
The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 9165938D90FDDD2E
Reading package lists… Done
W: GPG error: http://mirrordirector.raspbian.org/raspbian stretch InRelease: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 9165938D90FDDD2E
E: The repository ‘http://mirrordirector.raspbian.org/raspbian stretch InRelease’ is not signed.
N: Updating from such a repository can’t be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.’

When I try to install CMake in the software center default application, it wants me to ‘enable third-party software source’. When I click enable and install (The exact prompt is: CMake is provided by “pureos-green-main”. This software source must be enabled to continue installation.) is when I get the exact error message: ‘unable to install cmake as not supported’.

A few other small details: The CMake package as being 0 bytes in the software center GUI and “pureos-green-main” is underlined as though it is a hyperlink but there is no link. Using sudo apt upgrade after sudo apt update (which fails with error mentioned above) updated nodejs and slack on my computer.

Do you run PureOS? It seems you have raspbian repositories in your apt list.

You might be interested in the software sources wiki article.

What does the following command output?

cat /etc/apt/sources.list

Thank you. I had raspbian software sources and not pureOS default sources on.